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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 14A
(RULE 14a-101)
INFORMATION REQUIRED IN PROXY STATEMENT
SCHEDULE 14A INFORMATION

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IRON MOUNTAIN INCORPORATED

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IRON MOUNTAIN INCORPORATED

745 Atlantic Avenue
Boston, Massachusetts 02111

NOTICE OF 20042005 ANNUAL MEETING OF SHAREHOLDERS
TO BE HELD ON MAY 27, 200426, 2005

To the Shareholders of
    IRON MOUNTAIN INCORPORATED:

        Iron Mountain Incorporated will hold its 20042005 Annual Meeting of Shareholders at the offices of Sullivan & Worcester LLP, One Post Office Square, 21st21st Floor, Boston, Massachusetts, on May 27, 200426, 2005 at 10:00 a.m. local time for the following purposes:


        Attached to this notice is a Proxy Statement relating to the proposals to be considered at the Annual Meeting. The Board of Directors has fixed the close of business on April 5, 20048, 2005 as the record date for the determination of shareholders entitled to receive notice of and to vote at the Annual Meeting or at any adjournment or postponement thereof. In the event that the Annual Meeting is adjourned for at least 15 days due to the absence of a quorum, those shareholders entitled to vote who attend the adjourned meeting, although otherwise less than a quorum, shall constitute a quorum for the purpose of acting upon any matter set forth in this notice except with regard to Item 3 as set forth in the accompanying proxy statement.

        Your vote is important regardless of the number of shares you own. The Company requests that you complete, sign, date and return the enclosed proxy card without delay in the enclosed postage-paid return envelope, even if you now plan to attend the Annual Meeting. You may revoke your proxy at any time prior to its exercise by delivering written notice or another duly executed proxy bearing a later date to the Secretary of the Company, or by attending the Annual Meeting and voting in person.

        All shareholders are cordially invited to attend the Annual Meeting.

By order of the Board of Directors,



GARRY B. WATZKE,Secretary

Boston, Massachusetts
April 22, 200427, 2005


IRON MOUNTAIN INCORPORATED

745 ATLANTIC AVENUE
BOSTON, MASSACHUSETTS 02111

PROXY STATEMENT
FOR THE 2005 ANNUAL MEETING OF SHAREHOLDERS

To be held on May 27, 200426, 2005


GENERAL INFORMATION

        This Proxy Statement is furnished in connection with the solicitation of proxies by the Board of Directors (the "Board") of Iron Mountain Incorporated ("Iron Mountain" or the "Company") for use at the Annual Meeting of Shareholders (the "Annual Meeting") to be held on May 27, 200426, 2005 (the "Annual Meeting") or at any adjournment or postponement thereof.

        The Company's Annual Report to Shareholders for the year ended December 31, 20032004 is being mailed to shareholders with the mailing of this Proxy Statementproxy statement on or about April 22, 2004.27, 2005.

        Iron Mountain will bear all costs of solicitation of proxies. Brokers, banks, custodians and other fiduciaries will be requested to forward proxy soliciting materials to the beneficial owners of shares held of record by such persons, and the Company will reimburse them for their reasonable out-of-pocket expenses incurred in connection with the distribution of such proxy materials. Solicitation of proxies by mail may be supplemented by telephone, telecopier or personal solicitation by directors, officers or other regular employees of the Company (who will not receive any additional compensation for any solicitation of proxies), as well as the firm of Georgeson Shareholder, which has been retained by the Company to assist in the solicitation for a fee of approximately $7,500 plus reasonable expenses.

Revocability of Proxies

        Any shareholder giving a proxy in the enclosed form has the power to revoke it at any time before it is exercised. You may revoke your proxy by delivering to the Secretary of the Company at the address given above a written notice of revocation or another duly executed proxy bearing a later date. You may also revoke your proxy by attending the Annual Meeting and voting in person.

Record Date, Voting and Share Ownership

        Iron Mountain's common stock, $0.01 par value per share (the "Common Stock"), is the only class of voting securities outstanding and entitled to vote at the Annual Meeting. As of the close of business on April 5, 2004,8, 2005, the record date for the determination of shareholders entitled to notice of and to vote at the Annual Meeting, 85,843,184130,335,595 shares of Common Stock were outstanding and entitled to vote. Each share is entitled to one vote on each matter.

        The presence at the Annual Meeting, in person or by proxy, of shareholders entitled to cast at least a majority of the votes that all shareholders are entitled to cast at the Annual Meeting will constitute a quorum. Shares represented by a properly signed and returned proxy will be treated as present at the Annual Meeting for purposes of determining a quorum, without regard to whether the proxy is marked as casting a vote or abstaining. Shares represented by "broker non-votes" will not be treated as present for purposes of determining a quorum; however, shares voted by a broker on any issue other than a procedural motion will be considered present for all quorum purposes, even if the shares are not voted on every matter. A broker non-vote occurs on an item when a broker identified as the record holder of shares is not permitted to vote on that item without instruction from the beneficial owner of the shares and no instruction has been received.

        A proxy in the enclosed form, if received in time for voting and not revoked, will be voted at the Annual Meeting in accordance with the instructions contained therein. Where a choice is not so specified, the shares represented by the proxy will be counted:


        Abstentions or withheld votes and broker non-votes will not be counted as votes cast and, therefore, will not affect the election of the directors, the approval and adoption of the Charter AmendmentAgreement and Plan of Merger, the approval of the amendment to the 2003 Employee Stock Purchase Plan or the adoptionratification of the Plan Amendment.selection of the Company's independent public accountants.

        Our website address is included several times in this proxy statement as a textual reference only and the information in the website is not incorporated by reference into this proxy statement.

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ITEM 1

ELECTION OF DIRECTORS

        The Board has unanimously adopted resolutions approving an amendment to Sections 3.1(c) and (d) of our Bylaws to declassify the Board. Section 3.1(c) of our Bylaws previously provided that the Board be divided into three classes, as nearly equal in number as reasonably possible, with members of each class serving three-year terms. The amendment provides for the annual election of all directors in the manner described below. The Board currently consists of nine directors. While the amendment does not change the present numbereight directors, each of directors, the Board has separately determined to reduce the number of directors to eight effective as of the 2004 Annual Meeting. The Board will retain the authority to change that number and to fill any vacancies or newly created directorships.

        Classified or staggered boards have been widely adopted and have a long history in corporate law. Proponents of classified boards assert they promote the independence of directors because directors elected for multi-year terms are less subject to outside influence. Proponents of a staggered system for the election of directors also believe it provides continuity and stability in the management of the business and affairs of a company because a majority of directors always have prior experience as directors of the Company. Proponents further assert that classified boards may enhance shareholder value by forcing an entity seeking control of a target company to initiate arms-length discussions with the board of a target company because the entity is unable to replace the entire board in a single election.

        On the other hand, some investors view classified boards as having the effect of reducing the accountability of directors to shareholders because classified boards limit the ability of shareholders to evaluate and elect all directors on an annual basis. The election of directors is a primary means for shareholders to influence corporate governance policies and to hold management accountable for implementing those policies. In addition, opponents of classified boards assert that a staggered structure for the election of directors may discourage proxy contests in which shareholders have an opportunity to votewhom serves for a competing slate of nominees and therefore may erode shareholder value.

        Our Nominating and Governance Committee and Board have carefully considered the advantages and disadvantages of maintaining a classified board structure, and have concluded it is an appropriate time to declassify the Board. This determination by the Board furthers its goal of ensuring that the Company's corporate governance policies maximize management accountability to shareholders andone-year term which will allow shareholders the opportunity each year to register their views on the performance of the Board.

        In connection with the amendment to our Bylaws to declassify our Board and in order to implement the provisions thereof, each of our directors whose terms would not have otherwise expiredexpire at the 2004 Annual Meeting has executed a resignation whereby he will resign at the 2004 Annual Meeting. As a result, the terms for all of our directors will end at the 2004 Annual Meeting. At the Annual Meeting, all directors are to be elected for one-year terms to serve until the Company's 20052006 Annual Meeting of Shareholders, or until their successors are elected and qualified. Eugene B. Doggett's term as a director will also terminate as of the 2004 Annual Meeting and he has elected not to seek re-nomination as a director. The Board has elected to reduce the size of the Board to eight directors, and therefore is only nominating eight directors for election. The Board has selected as nominees the following individuals who are the current directors of the Company: Clarke H. Bailey, Constantin R. Boden, Kent P. Dauten, B. Thomas Golisano, John F. Kenny, Jr., Arthur D. Little, C. Richard Reese and Vincent J. Ryan. Each has agreed to serve if elected, and management has no reason to believe that any of the nominees will be unavailable to serve.

        The Company's executive officers were last elected as a group on May 22, 2003.27, 2004. At a meeting to be held immediately following the Annual Meeting, the Board currently intends to elect executive officers of the Company. All executive officers hold office at the discretion of the Board until the first meeting of

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the Board following the next annual meeting of shareholders or until they sooner die, resign or are removed. Except for T. Anthony Ryan, the Company's Senior Vice President, Real Estate, and Vincent J. Ryan, a director, who are brothers, there are no family relationships between or among any of the Company's officers or directors.

Required Vote

        The affirmative vote of holders of a plurality of the votes properly cast at the Annual Meeting is required to elect each director. For purposes of determining which nominees receive a plurality, only those cast "For" are included, and any abstentionswithheld votes or broker non-votes will not count in making that determination.

        The Board recommends that you vote FOR the election of each of the nominees listed below to serve as directors of Iron Mountain until the 20052006 Annual Meeting of Shareholders, or until their successors are elected and qualified.

        Set forth below is the name and age of each director nominated to serve an additional term, his principal occupation and business experience during the past five years and the names of certain other companies of which he served as a director, as of April 1, 2004.2005.

Nominee

 Principal Occupations and Business Experience
During the Past Five Years

Clarke H. Bailey
Age 4950
 Mr. Bailey ishas been one of our directors a position he has held since January 1998. Since 1990, Mr. Bailey serveshas served as Chief Executive Officer, Chairman and a director of Glenayre Technologies, Inc., a publicly held company engaged in the development and sale of software and equipment in the wireless communications industry.industry, and has served as its Chairman since June 1999 and its Chief Executive Officer since November 2003. Mr. Bailey was the Chairman and Chief Executive Officer of each of Arcus Group, Inc., United Acquisition Company and Arcus Technology Services, Inc. from 1995 until their acquisition by Iron Mountain in January 1998. Mr. Bailey is also a director of Tengasco, Inc. He holds a Master of Business Administration degree from The Wharton School, University of Pennsylvania.



Constantin R. Boden
Age 6768

 

Mr. Boden ishas been one of our directors a position he has held since December 1990. Since January 1995, Mr. Boden ishas been the principal of Boden Partners LLC. For 34 years, until January 1995, Mr. Boden was employed by The First National Bank of Boston, most recently as Executive Vice President, International Banking. He holds a Master of Business Administration degree from Harvard Business School.

Kent P. Dauten
Age 4849

 

Mr. Dauten ishas been one of our directors a position he has held since November 1997. He also serves as President of Keystone Capital, Inc., a management and consulting advisory services firm, a position he has held since March 1994. In February 1995, Mr. Dauten founded HIMSCORP, Inc. (d/b/a Records Masters) and served as its President until its acquisition by Iron Mountain in November 1997. Mr. Dauten currently serves as a director of Health Management Associates, Inc., a hospital management firm. Mr. Dauten holds a Master of Business Administration degree from Harvard Business School.

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B. Thomas Golisano
Age 6263

 

Mr. Golisano ishas been one of our directors a position he has held since June 1997. Mr. Golisano was Chairman of Safesite Records Management Corporation until its acquisition by Iron Mountain in June 1997. He founded Paychex Inc., a publicly held, national payroll service company, in 1971 and servesserved as its Chairman, President and Chief Executive Officer.Officer until 2004. Mr. Golisano continues to serve as the Chairman of the Board of Directors of Paychex, Inc. Mr. Golisano serves on the Board of Trustees of Rochester Institute of Technology and on the boards of several privately held companies. He also serves on the boards of numerous non-profit organizations and is the founder of the B. Thomas Golisano Foundation.

John F. Kenny, Jr.
Age 4647

 

Mr. Kenny ishas been one of our directors a position he has held since March 2000. He is also an Executive Vice President and the Chief Financial Officer of the Company, positions he has held since May 1997. Mr. Kenny joined Iron Mountain in 1991 and held a number of operating positions before assuming the position of Vice President of Corporate Development in 1995. Mr. Kenny has also served as a director and the Treasurer of Professional Records and Information Services Management ("PRISM"), a trade group with approximately 530580 members. He holds a Master of Business Administration degree from Harvard Business School.

Arthur D. Little
Age 6061

 

Arthur D. Little ishas been one of our directors a position he has held since November 1995. Mr. Little is a principal of A & J Acquisition Company, Inc., which he founded in 1996. He holds a Bachelor of Arts degree in history from Stanford University.

C. Richard Reese
Age 5859

 

Mr. Reese ishas been one of our directors a position he has held since 1990,1990. Mr. Reese is Chairman of the Board, a position he has held since November 1995, and the Chief Executive Officer of the Company, a position he has held since 1981. He is also the President of the Company, a position he has held since June 2000 and previously held from 1981 until Novemberto 1985. Mr. Reese is a member of the investment committee of Schooner Capital, LLC ("Schooner"), a shareholder in the Company. Mr. Reese has also served as the President and a director of PRISM. He is also a director of Ardais Corporation, Bird Dog Solutions, Inc. and Continental Fire, Inc. He holds a Master of Business Administration degree from Harvard Business School.


Vincent J. Ryan
Age 6869

 

Mr. Ryan ishas been one of our directors a position he has held for over ten years.since prior to 1990. Mr. Ryan is the founder of Schooner and its predecessor, Schooner Capital Corporation. Mr. Ryan has served as the Chairman and Chief Executive Officer of Schooner since 1971, and as its President from 1971 to 1985 and from 1996 to 1999. Prior to November 1995, Mr. Ryan served as Chairman of Iron Mountain's Board.

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        Set forth below is the name and age of each executive officer of the Company who is not a director of the Company, his principal occupation and business experience during the past five years and the names of certain other companies of which he served as a director, as of April 1, 2004.2005.

Name

 Principal Occupations and Business Experience
During the Past Five Years

Peter E. Delle DonneRobert T. Brennan
Age 5846
 Mr. Delle Donne is an Executive Vice PresidentRobert T. Brennan assumed the role of the Company and the President of Iron Mountain Enterprise Solutions and Services, a division ofMountain's North American businesses in November 2004. Mr. Brennan joined Iron Mountain Information Management,through the acquisition of Connected Corporation, where he served as Chief Executive Officer since 2000. Before Connected, Mr. Brennan was a general manager with Cisco Systems, Inc. ("IMIM"Cisco") for network and service management. Mr. Brennan also served as Chief Executive Officer of American Internet Corporation prior to its acquisition by Cisco in 1998. From 1993 to 1995, Mr. Brennan was the vice president, general manager for Merisel Inc., a wholly owned subsidiarydistributor of the Company. Prior to February 1, 2003, Mr. Delle Donne was the President ofsoftware and microcomputer products. He holds a Bachelor's degree in psychology from Manhattan College.

Jean A. Bua
Age 46


Ms. Bua joined Iron Mountain Digital Archives, a division of IMIM, a position to which he was appointed on May 1, 2001. From 1999 through May 1, 2001, Mr. Delle Donne was Vice President of the North America Enterprise Storage Group, and then Vice President, Worldwide Enterprise Storage Products and Services Solutions for Compaq Computer Corporation. Mr. Delle Donne served as Vice President and General Manager, American Power Conversion,Corporate Controller in 1996. She was appointed Chief Accounting Officer in 2003 and was elected to the office of Senior Vice President in 2005. Ms. Bua is a Certified Public Accountant and holds a Master of Business Administration degree from 1998 through 1999.the University of Rhode Island.

John Connors
Age 49


Mr. Connors was appointed Executive Vice President, Sales and Marketing in February 2005. From 1999 to 2005, Mr. Connors served as Chief Executive Officer of Intrinsiq Research, a privately held company in the field of chemotherapy management software and information for the cancer care market. Prior to 1999, Mr. Connors served, at different times, as Chief Executive Officer of Molecular Insight Pharmaceuticals, Inc. and Kidsoft, LLC and as President of Merisel, Inc.

Harold E. Ebbighausen
Age 4950

 

Mr. Ebbighausen is an Executive Viceassumed the role of Group President of the Company andNorth American Service Delivery in December 2004. From 1998 through 2004, he served as the President of Iron Mountain Off-Site Data Protection ("IMOSDP"), a division of IMIM.Iron Mountain Information Management, Inc. ("IMIM"). Prior to September 10, 2001, IMOSDP was a separate subsidiary known as Arcus Data Security, Inc. Mr. Ebbighausen has been an Executive Vice President of the Company since July 1997 and had been the President of Arcus Data Security, Inc. since July 1998.

Robert G. MillerKenneth F. Radtke, Jr.
Age 4759

 

Mr. Miller is an Executive Vice President of the Company and the President of Iron Mountain Records Management ("IMRM"), a division of IMIM. Mr. MillerRadtke was appointed President of Iron Mountain Records Management, Inc. ("IRM"), the predecessor of IMIM,Europe in March 2001 and had served as the Senior Vice President and Chief Operating Officer of IRM from July 2000, until his appointment as President. Prior to July 2000, Mr. Miller was2000. Previously an Executive Vice President since 1996, Mr. Radtke joined Iron Mountain in 1994 and has held several sales and field management positions. Mr. Radtke holds a Bachelor of IRM,Arts degree from Elmhurst College and a position that he had held since December 1996.graduate banking degree from the University of Wisconsin.

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Director Compensation

        Directors who are employees of the Company do not receive additional compensation for serving as directors. Each director who is not an employee of the Company receives an annual retainer fee of $20,000 as compensation for his services as a member of the Board and $1,000 for attendance at Board and committee meetings. In addition, committee chairmen of the Compensation and Nominating and Governance Committees receive an annual retainer of $5,000; the chairman of the Audit Committee receives an annual retainer of $20,000; and the "lead director" receives an annual retainer of $25,000. The Company also has a program by which it grants its nonemployee directors options to purchase shares of the Company's Common Stock every three years in an amount such that the product of the exercise price and the number of shares covered by the grant equals $200,000. Each such option has an exercise price equal to fair market value (as defined in the relevant plan)plan under which it is granted) on the date of grant, vests in equal amounts over a period of three years (subject to the optionee's continuing to be a director) and has a ten year term. Options have been and will continue to be granted under the Iron Mountain Incorporated 2002 Stock Incentive Plan (the "2002 Stock Incentive Plan"). All directors are reimbursed for out-of-pocket expenses incurred in attending meetings of the Board or committees thereof, and for other expenses incurred in their capacities as directors. The Company paid a total of $178,000$216,800 in cash for directors fees in respect of services for 2003.2004.

Board of Directors and Committees

        Independence.    TheOur Board is comprised of a majority of directors who qualify as independent directors pursuant to the corporate governance standards for companies listed on the New York Stock Exchange ("NYSE"). In determining independence pursuant to NYSE standards, each year the Board affirmatively determines whether directors have a direct or indirect material relationship with the Company, including its subsidiaries, that may interfere with their ability to exercise their independence from the Company. When assessing the materiality of a director's relationship with the Company, the Board considers all relevant facts and circumstances, not merely from the director's standpoint, but from that of the persons or organizations with which the director has an affiliation. Material relationships can include commercial, industrial, banking, consulting, legal, accounting, charitable and familial relationships.

        The Board has determined that the following directors qualify as independent under NYSE rules: Messrs. Bailey, Boden, Dauten, Golisano and Little. The Board has also determined that Mr. Doggett, who is not seeking re-nomination, is an independent director under the NYSE rules. TheOur Board has concluded that none of these directors possessed the categorical relationships set forth in the NYSE listing standards that prevent independence. None of our independent directors has any relationship with the Company other than his service as a director and on committees of the Board.

        Two of our directors, Messrs. Kenny and Reese, are management employees involved in our day to day activities and are not considered to be independent directors. Additionally, although none of the relationships Mr. Ryan has with the Company would be sufficient to classify him as not independent under NYSE rules, the Board has determined not to consider Mr. Ryan as an independent director due to his position with Schooner, the familial relationship between Mr. Ryan and T. Anthony Ryan, an officer of the Company, and Schooner's lease with the Company.

        Attendance.    During the fiscal year ended December 31, 2003,2004, the Board held four regular meetings and fourthree special meetings and took one actiontwo actions by written consent. EachExcept for Mr. Golisano, who attended five of the seven meetings held by the Board, each incumbent director attended at least 75% of the aggregate number of meetings of the Board and all committees thereof on which such director served. AllExcept for Mr. Golisano, all of our directors attended our 20032004 annual meeting of shareholders. All directors are expected to attend the annual meeting of shareholders.Annual Meeting. Our policy with respect to directors' attendance at our annual meetings of shareholders can be found in our corporate governance guidelines, the full text of which appears in the "Investor Relations/Governance" section of our website at www.ironmountain.com. A printed copy of our corporate governance guidelines is also available free of charge to any shareholder who requests a copy.

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        Committees.    The Board of the Company has a standing Audit Committee, Executive Committee, Nominating and Governance Committee and Compensation Committee and Stock Incentive Plan Subcommittee of the Compensation Committee (the "Incentive Plan Subcommittee").Committee. The Board has adopted charters for the Audit Committee, Compensation Committee and Nominating and Governance Committee, each of which is available on our website at www.ironmountain.com under the heading "Investor Relations/Governance." A printed copy of these charters is also available free of charge to any shareholder who requests a copy. The Board and each of the Audit Committee, Compensation Committee and Nominating and Governance Committee have conducted and will continue to conduct annual self-evaluations. These self-evaluations are intended to facilitate an examination and discussion by the entire Board and each of these committees of their effectiveness as a group in fulfilling charter requirements and other responsibilities, as well as areas for improvement. During the fiscal year ended December 31, 2003,2004, the Audit Committee held eightnine meetings, the Executive Committee held fivethree meetings and took two actions by written consent, the Compensation Committee held five meetings and took three actions by written consent and the Nominating and Governance Committee held one meeting and the Incentive Plan Subcommittee held three meetings.meeting.

        Audit Committee.    The Audit Committee consists of three members, Messrs. Boden (Chairman), Little and Dauten, each of whom is independent as defined by the rules of the Securities and Exchange Commission ("SEC"), NYSE listing standards and the Audit Committee Charter. The Board has determined that Mr. Boden is an audit committee financial expert as defined by the rules of the SEC. Additionally, the Board has determined that each of the three members of the Audit Committee is financially literate as defined by the NYSE listing standards. The Audit Committee operates under a written charter adopted by the Board, which is attached to this proxy as Appendix A. The Audit Committee (1) assists the Board in oversight of the integrity of the Company's financial statements, (2) assists the Board in oversight of the Company's compliance with legal and regulatory requirements, (3) assists the Board in oversight of the independent auditor's qualifications and independence, (4) assists the Board in oversight of the performance of the Company's internal audit function and independent auditors, (5) prepares an Audit Committee report as required by the SEC to be included in the annual proxy statement, (6) performs such other duties as the Board may assign to the Committee from time to time and (7) takes other actions to meet its responsibilities as set forth in its written charter. The Audit Committee is also responsible for establishing procedures for the receipt, retention and treatment of complaints regarding accounting, internal accounting controls and auditing matters, including procedures for the confidential and anonymous submission by employees of the Company of any concerns regarding accounting or auditing matters they think may be questionable. Information about these procedures can be found on our website inunder the "Investor Relations/Governance"Governance section under the "E-mail"E-Mail Alert" heading at www.ironmountain.com.

        Executive Committee.    The Executive Committee consists of Messrs. Ryan (Chairman), Reese and Bailey. Between meetings of the Board, the Executive Committee exercises all the powers of the Board in the management and direction of the business and affairs of the Company to the extent not otherwise prohibited by law, the Board, the Company's Amended and Restated Bylaws or Amended and Restated Articles of Incorporation.

        Compensation Committee.    For the year ended December 31, 2003, theThe Compensation Committee consistedconsists of Messrs. Bailey (Chairman), Boden Little and Ryan. Each of these directors is independent as defined by NYSE listing standards with the exception of Mr. Ryan, who, asLittle. As discussed above under "Independence," the Company has determined not to consider independent. Mr. Ryan hasindependent under NYSE listing standards; consequently, Mr. Ryan resigned from the Compensation Committee effective March 5, 2004. Upon Mr. Ryan's resignation, all of the members of the Compensation Committee qualify as independent under NYSE listing standards. The Compensation Committee (1) recommends to the Board the chief executive officer's and other executive officers' annual compensation, (2) creates shareholder value by ensuring market-driven, competitive and equitable compensation systems for senior officers that create both short- and long-term incentives, (2)(3) takes actions to retain a skilled, creative and professional management team at the most economical cost, (3)(4) ensures that compensation policies and programs are compliant with applicable laws and are

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administered without bias or prejudice, (4)(5) takes actions to maintain a



compensation philosophy of "paying for performance" for senior management, (5)(6) develops and proposes for consideration by the Board compensation policies for the Company's non-employee directors that enable the Company to retain highly qualified individuals for such positions and (6)(7) takes other actions to meet its responsibilities as set forth in its written charter.

        Nominating and Governance Committee.    The Nominating and Governance Committee consists of Messrs. Little (Chairman), Boden and Golisano each of whom isqualify as independent as defined byunder NYSE listing standards. The Nominating and Governance Committee (1) recommends the composition and size of the Board, (2) identifies and recommends candidates for nomination to the Board, (3) recommends to the Board statements of the duties and responsibilities of each committee and subcommittee of the Board, (4) develops and recommends to the Board and implements corporate governance guidelines applicable to the Company, (5) assists the Board in reviewing management succession, (6) develops and monitors an annual process to assess the effectiveness of the Board and the Board's standing committees and (7) takes other actions to meet its responsibilities as set forth in its written charter.

        Incentive Plan Subcommittee.    The Incentive Plan Subcommittee consists of Messrs. Little (Chairman) and Boden, both of whom are "outside" and "non-employee" directors within the meaning of Section 162(m) of the Internal Revenue Code of 1986, as amended (the "Code"), and the regulations thereunder, and Rule 16b-3 under Section 16 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), respectively. The Incentive Plan Subcommittee currently administers the 2002 Stock Incentive Plan, including the grant of stock options under the 2002 Stock Incentive Plan to all employees, including executive officers and directors. The Incentive Plan Subcommittee also administers the 2003 Employee Stock Purchase Plan (the "ESPP"), the Iron Mountain Incorporated 1995 Stock Incentive Plan (the "1995 Plan"), the Iron Mountain Incorporated 1997 Stock Option Plan (the "1997 Plan"), the Iron Mountain/ATSI 1995 Stock Option Plan and the Nonqualified Stock Option Plan of Pierce Leahy Corp., and recommends the adoption of, and any amendments to, all stock incentive plans. There are no shares available for grant under the 1995 Plan and the 1997 Plan, other than shares that become available under such plans in the future as a result of the lapse or cancellation of outstanding stock options. There are no shares available for grant under the Iron Mountain/ATSI 1995 Stock Option Plan or the Nonqualified Stock Option Plan of Pierce Leahy Corp. The Incentive Plan Subcommittee also administers the Iron Mountain Incorporated Executive Deferred Compensation Plan, a nonqualified deferred compensation plan (the "Executive Deferred Compensation Plan").

Meetings of Independent/Non-Management Directors

        In accordance with NYSE listing standards and pursuant to our Corporate Governance Guidelines, our non-management directors meet at regularly scheduled executive sessions and may hold such additional executive sessions as they determine necessary or appropriate. One of our non-management directors, Mr. Ryan, has been determined by the Board not to be considered independent as defined by the NYSE listing standards; the independent directors meet at least once each year without such non-independent director. The Board has named Mr. Boden as the lead director and he acts as the chair of the executive sessions.

Shareholder Communications to Board of Directors

        The Board believes it is important for shareholders and others to have a process to send communications to the Board. Accordingly, any shareholder, security holder or other interested party who desires to communicate with the Board, any individual director, including the lead director, or the independent or non-management directors as a group, may do so by regular mail or e-mail directed to the Secretary of the Company. The Secretary's mailing address is c/o Iron Mountain, 745 Atlantic Avenue,

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Boston, Massachusetts 02111; the Secretary's e-mail address is corporatesecretary@ironmountain.com. Upon receiving mail addressed to the Board, the Secretary will assess the appropriate director or directors to receive the message, and will forward the mail to such director or directors without editing or altering it.

Selection of Candidates for Directors

        The Board as a whole is responsible for nominating individuals for election to the Board by the shareholders and for filling vacancies on the Board that may occur between annual meetings of the shareholders. The Board is also responsible for developing and approving criteria, in addition to those set forth in our Corporate Governance Guidelines, for candidates for Board membership. The Nominating and Governance Committee is responsible for seeking candidates to become Board members, consistent with the criteria set forth in the Corporate Governance Guidelines and approved by the Board, and for recommending candidates to the entire Board for selection by the Board for nomination to fill vacancies on the Board or expiring terms of directors at each annual meeting of shareholders.

        Nominees for director will be selected on the basis of their integrity, experience, achievements, judgment, intelligence, personal character, ability to make independent analytical inquiries, willingness to devote adequate time to Board duties, and likelihood that he or she will be able to serve on the



Board for a sustained period. The Nominating and Governance Committee will consider, as part of the process for identifying individuals who might be candidates, individuals who are properly recommended by shareholders for nomination by the Board at a meeting of shareholders at which directors are to be elected. To be proper, a recommendation for a nominee for director with respect to a meeting of shareholders must comply with applicable law, the Company's bylaws,Bylaws, the Nominating and Governance Committee Charter and the Company's Corporate Governance Guidelines. The Nominating and Governance Committee will consider any suggestions offered by other directors or shareholders with respect to potential directors and there will be no difference in the manner in which potential nominees are evaluated. However, the Nominating and Governance Committee, and the Board, will not be required to enlarge the size of the Board in order to nominate an otherwise fully qualified candidate proposed by a shareholder.

        In 2003,2004, we did not pay a fee to any third party to identify or evaluate or assist in identifying or evaluating potential nominees for our Board. We did not, as of December 19, 2003,the February 21, 2005 deadline, receive any recommendations from shareholders for nominees for the Board.

Nominations and Proposals of Shareholders

        The Company expects to hold the 20052006 Annual Meeting on May 26, 2005.25, 2006.

     ��        To be eligible for consideration at our 20052006 Annual Meeting, shareholder nominations of a person (or persons) to be elected as a director (or directors) must be received at our principal executive office no earlier than December 23, 2004,January 27, 2006, and no later than January 22, 2005.February 26, 2006. Shareholder nominations must also be made in compliance with the other requirements for shareholder nominations set forth in our Bylaws and Corporate Governance Guidelines.

        A shareholder who intends to present a proposal at the 20052006 Annual Meeting of Shareholders and who wants the proposal included in the Company's 20052006 proxy statement and proxy card relating to that meeting must submit the proposal by December 23, 2004.28, 2005. In order for the proposal to be included in the proxy statement, the shareholder submitting the proposal must meet certain eligibility standards and comply with certain procedures established by the SEC, and the proposal must comply with the requirements as to form and substance established by our Bylaws and applicable laws and regulations. The proposal must be mailed to the Company's principal executive office, at the address stated herein, and should be directed to the attention of the Chief Financial Officer.

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        A shareholder who intends to present a proposal at the 20052006 Annual Meeting of Shareholders and who intends to conduct his, her or its own proxy solicitation must submit the proposal to the Company notno earlier than January 22, 200527, 2006 and not later than February 21, 2005.26, 2006.

Code of Ethics

        We have adopted a Code of Ethics and Business Conduct that applies to each employee, including officers, of the Company and all directors. Our Code of Ethics and Business Conduct is posted on our website at www.ironmountain.com under the heading "Investor Relations/Governance." A printed copy of our Code of Ethics and Business Conduct is also available free of charge to any shareholder who requests a copy. We intend to satisfy our disclosure requirement regardingdisclose any amendment to, or waiver from, a provision of our Code of Ethics and Business Conduct applicable to the Company's chief executive officer, chief financial officer or principal accounting officer or controller by posting such information on our website or in a report on Form 8-K.website. Any waivers applicable to any other executive officers will also be promptly disclosed to shareholders on our website.

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ITEM 2

AMENDMENT TOAPPROVAL OF THE COMPANY'S AMENDED AND RESTATED
ARTICLESREINCORPORATION OF INCORPORATION TO INCREASE THE AUTHORIZED SHARESCOMPANY
INTO THE STATE OF COMMON STOCKDELAWARE

        For the reasons set forth below, the Company's Board approved a proposal to change the Company's state of incorporation from Pennsylvania to Delaware (the "Reincorporation") and believes that the Reincorporation is in the best interests of the Company and its shareholders. Throughout this Item 2, the Company as currently incorporated in Pennsylvania will be referred to as "Iron Mountain PA" and the Company as reincorporated in Delaware will be referred to as "Iron Mountain DE".

        Shareholders are urged to read carefully this section of this Proxy Statement, including the related appendices referenced below and attached to this Proxy Statement, before voting on the Reincorporation.

Proposed AmendmentMethod of Reincorporation

        The Pennsylvania General Corporation Law provides thatReincorporation will be effected by merging Iron Mountain PA into its wholly owned Delaware subsidiary, Iron Mountain DE, pursuant to an Agreement and Plan of Merger (the "Merger Agreement"), in the totalform attached hereto as Appendix A. On the effective date of the merger, Iron Mountain DE will succeed to the assets and liabilities of, and possess all the rights and powers of, Iron Mountain PA and will continue to operate the business of the Company under its current name, Iron Mountain Incorporated. The Reincorporation will effect only a change in the legal domicile of the Company and other changes of a legal nature. The material changes are described in this Proxy Statement. The Reincorporation will NOT result in any change in the Company's business, management, capitalization, Board structure or membership, fiscal year, assets, liabilities or the location of the Company's principal facilities or headquarters. The Reincorporation is not expected to have a material effect on state or federal taxation of the Company. The directors elected at the Annual Meeting to serve as directors of Iron Mountain PA will become directors of Iron Mountain DE.

        At the effective time of the merger, each issued and outstanding share of Common Stock will be automatically converted into one share of Iron Mountain DE common stock, $0.01 par value per share. Each stock certificate representing issued and outstanding shares of Common Stock will continue to represent the same number of shares of Iron Mountain DE common stock. Shareholders will not need to exchange their existing Common Stock certificates for Iron Mountain DE stock certificates but may do so if they would prefer. Any such request should be directed to the Company's transfer agent, The Bank of New York, Receive & Deliver Department, P.O. Box 11002, Church Street Station, New York, NY 10286, 800-524-4458. After the Reincorporation, certificates representing Common Stock will constitute "good delivery" in connection with sales through a broker, or otherwise, of shares of Iron Mountain DE common stock. Iron Mountain PA's transfer agent, The Bank of New York, will act as transfer agent for Iron Mountain DE after the Reincorporation. Shareholders may consult their stockbrokers or the Company with respect to any questions regarding the mechanics of these types of transactions.

        All employee benefit, stock option and employee stock purchase plans of Iron Mountain PA will become Iron Mountain DE plans, and each option or right issued by such plans will automatically be converted into an option or right to purchase the same number of shares of Iron Mountain DE common stock, at the same price per share, upon the same terms and subject to the same conditions. Shareholders should note that approval of the Reincorporation will also constitute approval of these plans continuing as Iron Mountain DE plans. Other employee benefit arrangements of Iron Mountain PA will also be continued by Iron Mountain DE upon the terms and subject to the conditions currently in effect. The Company believes that the Reincorporation will not affect any of its material contracts with any third parties and that Iron Mountain PA's rights and obligations under such material contractual arrangements will continue as rights and obligations of Iron Mountain DE.



        The Common Stock is listed for trading on the New York Stock Exchange and, after the merger, Iron Mountain DE common stock will be traded on the New York Stock Exchange under the same symbol, "IRM", as the shares of Common Stock are currently traded. The shares of Iron Mountain DE common stock will continue to be represented by the same CUSIP number that is currently used for the Common Stock. There will be no interruption in the trading of the Common Stock as a result of the merger.

        The Reincorporation includes the implementation of a new certificate of incorporation, in the form attached hereto as Appendix B (the "Delaware Charter") and bylaws, in the form attached hereto as Appendix C (the "Delaware Bylaws") for Iron Mountain DE to replace the current articles of incorporation and bylaws of Iron Mountain PA (the "Pennsylvania Charter" and "Pennsylvania Bylaws", respectively). As a Delaware corporation, Iron Mountain DE will be subject to the Delaware General Corporation Law (the "DGCL"). Iron Mountain PA is subject to the Business Corporation Law of Pennsylvania (the "PaBCL"). Differences between the Delaware Charter and Delaware Bylaws, on the one hand, and the Pennsylvania Charter and Pennsylvania Bylaws, on the other hand, must be viewed in the context of the differences between the DGCL and the PaBCL. Material differences are discussed below under "—Comparison of the Charters and Bylaws of Iron Mountain PA and Iron Mountain DE and Significant Differences Between the Corporation Laws of Delaware and Pennsylvania".

        If approved by the shareholders, it is anticipated that the Reincorporation will be completed as soon thereafter as is practicable. As described in the Merger Agreement, however, the Board may abandon the Reincorporation or amend the Merger Agreement, subject to any restrictions imposed by the DGCL or the PaBCL, either before or after shareholder approval has been obtained if, in the opinion of the Board, circumstances arise that make such action advisable. Any amendment that would adversely affect Iron Mountain PA shareholders or effect a material change from the Delaware Charter in the form attached hereto and described herein, however, would require further approval by the holders of a majority of the outstanding shares of the Common Stock. The Board does not currently intend to make any material amendments to the Merger Agreement, nor does it intend to amend the Delaware Charter or Delaware Bylaws, in the forms attached hereto and described herein, should the Reincorporation be approved by the Company's shareholders.

        As provided in the PaBCL, Iron Mountain PA shareholders will not be entitled to exercise dissenters' rights or to demand payment for their shares in connection with the merger or the Reincorporation. See "—Comparison of the Charters and the Bylaws of Iron Mountain PA and Iron Mountain DE and Significant Differences Between the Corporation Laws of Delaware and Pennsylvania—Dissenters' Rights of Appraisal" below.

The following discussion summarizes certain aspects of the Reincorporation. The summary is not intended to be complete and is qualified in its entirety by reference to the Merger Agreement, the Delaware Charter and the Delaware Bylaws, copies of which are attached to this Proxy Statement as Appendices A, B and C, respectively, the DGCL and the PaBCL.

Principal Reasons for the Reincorporation in Delaware

        For many years, Delaware has followed a policy of encouraging incorporation in that state. In furtherance of that policy, Delaware has adopted comprehensive, modern and flexible corporate laws which are periodically updated and revised to meet changing business needs. Many corporations have initially chosen Delaware for their domicile, or have chosen to reincorporate in Delaware in a manner similar to that proposed by the Company. The Board believes the Reincorporation to be in the best interest of the Company and its shareholders for several reasons including, but not limited to:


Comparison of the Charters and the Bylaws of Iron Mountain PA and Iron Mountain DE and Significant Differences Between the Corporation Laws of Delaware and Pennsylvania

        As a result of the Reincorporation, Iron Mountain PA shareholders will become stockholders of Iron Mountain DE and the rights of all such former Iron Mountain PA shareholders will thereafter be governed by the Delaware Charter, the Delaware Bylaws and the DGCL. The rights of the Iron Mountain PA shareholders are presently governed by the Pennsylvania Charter, the Pennsylvania Bylaws and the PaBCL.

        The following summary, which does not purport to be a complete statement of the differences among the rights of the Iron Mountain DE stockholders and the Iron Mountain PA shareholders, sets forth certain differences between the DGCL and the PaBCL, between the Delaware Charter and the Pennsylvania Charter, and between the Delaware Bylaws and the Pennsylvania Bylaws. This summary is qualified in its entirety by reference to the full text of each of the documents, the DGCL and the PaBCL. The Delaware Charter and Delaware Bylaws are attached as Appendices B and C, respectively. Shareholders of the Company may obtain copies of the Pennsylvania Charter and Pennsylvania Bylaws at no cost by writing or telephoning us at: 745 Atlantic Avenue, Boston, Massachusetts 02111 Attention: Investor Relations, (617) 535-4799.

Limitations on Director Liability

        The DGCL permits a corporation to include a provision in its certificate of incorporation eliminating or limiting the personal liability of a director or officer to a corporation or its stockholders for damages for certain breaches of the director's fiduciary duty. This provision may not eliminate or limit the liability of a director for:

        Under the PaBCL and the Pennsylvania Bylaws, directors are liable for monetary damages only where the director has breached or failed to perform his or her duties under the PaBCL and that breach or failure to perform constitutes self-dealing, willful misconduct or recklessness. This limitation on liability does not extend to liability under a criminal statute or for the payment of taxes.

        The Delaware Charter eliminates the liability of directors to the fullest extent permissible under Delaware law. The Reincorporation and associated measures result in a director being shielded from suits by Iron Mountain DE or its stockholders for monetary damages for negligence or gross negligence by the director in failing to satisfy the director's duty of care. Consequently, an action for monetary damages against a director predicated on a breach of the duty of care will be available only if Iron Mountain DE or its stockholders are able to establish that the director was disloyal in his conduct,



failed to act in good faith, engaged in intentional misconduct, knowingly violated the law, derived an improper personal benefit or approved an illegal dividend or stock repurchase. The effect of such measures may be to limit or eliminate a remedy which might otherwise be available to a stockholder of Iron Mountain DE who is dissatisfied with the Board's decisions. Although an aggrieved stockholder could sue to enjoin or rescind an action taken or proposed by the Board, such remedies may not be timely or adequate to prevent or redress injury in all cases. On the other hand, there may be circumstances in which the DGCL and the Delaware Charter permit the Company or the stockholders to act against a director where the director's conduct would not be actionable under the PaBCL, such as breaches of a director's duty of loyalty or failure to perform his or her duties, that does not constitute self-dealing, willful misconduct or recklessness.

Indemnification of Officers and Directors

        The DGCL permits indemnification of officers and directors against liability incurred in third-party actions if the indemnitee acted in good faith and he or she reasonably believed the acts were in, or at least not opposed to, the best interests of the Company. Delaware law states that the indemnification provided by statute shall not be deemed exclusive of any other rights under any bylaw, agreement, vote of stockholders or disinterested directors or otherwise. As a result, under Delaware law, a Delaware corporation is permitted to indemnify its directors and officers within the limits established by law and public policy pursuant to an express contract, bylaw provision, stockholder vote, vote of disinterested directors or otherwise, any or all of which provide broad indemnification rights.

        The provisions of the PaBCL regarding indemnification are substantially similar to those of the DGCL. Under the PaBCL, Iron Mountain PA is permitted to indemnify its officers and directors so long as the indemnified person acted in good faith and in a manner he or she reasonably believed to be in, or not opposed to, the Company's best interests and, with respect to any criminal proceeding, had no reasonable cause to believe his or her conduct was unlawful. Pennsylvania law states that the indemnification provided by statute shall not be deemed exclusive of any other rights under any bylaw, agreement, vote of shareholders or disinterested directors or otherwise. Under the Pennsylvania Bylaws no indemnification is provided in the case of willful misconduct or recklessness.

Statutory Anti-Takeover Measures

        Delaware law permits a corporation to adopt a number of measures designed to reduce a corporation's vulnerability to hostile takeover attempts. Although the Board has not adopted or proposed any of these permitted anti-takeover measures at this time, there can be no assurance that the Board will not adopt anti-takeover measures available under Delaware law in the future. The availability of such measures under Delaware law, whether or not implemented, may have the effect of discouraging a future takeover attempt which a substantial number, or even a majority, of Iron Mountain DE's stockholders may deem to be in their best interests or in which stockholders may receive a premium for their shares over then current market prices. As a result, stockholders who might desire to participate in such transactions may not have the opportunity to do so.

        In addition to permitted anti-takeover measures, for certain corporations, Section 203 of the DGCL ("Section 203") limits the ability of a potential acquirer to conduct a hostile takeover. Under Section 203, certain "business combinations" by Delaware corporations with "interested stockholders" are subject to a three-year moratorium unless (1) prior to the date the stockholder became an "interested stockholder", the board of directors approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder, (2) upon becoming an interested stockholder, the stockholder then owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced (excluding certain shares), or (3) at or subsequent to the date the stockholder became an "interested stockholder", the "business combination" is approved by the board of directors and authorized at an annual or special meeting by at least 662/3%



of the corporation's outstanding voting stock, excluding shares owned by the interested stockholder unless the corporation's board of directors or stockholders has given a level of approval, or unless the "interested stockholder" owns at least 5% of the stock of the corporation. For purposes of Section 203, the term "business combination" includes mergers, asset sales and other similar transactions, and an "interested stockholder" is a person who, together with affiliates and associates, owns (or within the prior three years, did own) 15% or more of the corporation's voting stock. In effect, Section 203 prohibits a Delaware corporation from engaging in a "business combination" with an "interested stockholder" for three years following the date that person becomes an interested stockholder. As with other anti-takeover provisions, it is anticipated that the provisions of Section 203 of the DGCL may encourage companies interested in acquiring Iron Mountain DE to negotiate in advance with the Board, since the stockholder approval requirement would be avoided if a majority of the directors then in office approve either the business combination or the transaction which results in the stockholder becoming an interested stockholder. Section 203 also has the effect of limiting the ability of a potential acquirer to make a two-tiered bid for Iron Mountain DE in which all stockholders would not be treated equally.

        Section 203 only applies to Delaware corporations which have a class of voting stock that is (1) listed on a national securities exchange, (2) authorized for quotation on the Nasdaq Stock Market or (3) held of record by more than 2,000 stockholders. Because Iron Mountain DE common stock will be traded on the NYSE, Section 203 is applicable to Iron Mountain DE. A Delaware corporation may elect not to be governed by Section 203 by a provision in its original certificate of incorporation or an amendment thereto or to the bylaws, which amendment must be approved by a majority stockholder vote and may not be further amended by the board of directors. Section 203 will be applicable to Iron Mountain DE because the Delaware Charter does not contain an election to opt out of being governed by Section 203.

        The Board recognizes that hostile takeover attempts do not always have unfavorable consequences or effects and may frequently be beneficial to the stockholders, providing all of the stockholders with considerable value for their shares. The Board believes, however, that the potential disadvantages of unapproved takeover attempts, such as disruption of the Company's business and the possibility of terms which may be less favorable to all of the stockholders than would be available in a board-approved transaction, are sufficiently great that prudent steps to reduce the likelihood of such takeover attempts and to enable the Board to fully consider a proposed takeover attempt and actively negotiate its terms are in the best interests of the Company and its stockholders.

        The PaBCL contains provisions applicable to publicly held Pennsylvania corporations that may be deemed to have an anti-takeover effect. Subchapters 25 D, E, F, G, H, I and J of the PaBCL contain a variety of such measures, including restrictions on certain mergers and other business combinations and restrictions on the acquisition of shares which would entitle the acquiring person to cast a specified percentage of votes in an election of directors.

        Subchapter 25D (relating to fundamental changes) provides generally that certain transactions involving "interested shareholders," including mergers, consolidations, share exchanges, asset sales, divisions, voluntary dissolutions and winding up and certain reclassifications affecting the voting or share interests, require an affirmative vote of the majority of the votes entitled to be cast, without counting the vote of the interested shareholder, unless the board of directors approves the transaction or another exception applies. An "interested shareholder" is defined to include any shareholder who is a party to the covered transaction or who is treated differently from other shareholders in connection with such a transaction and any person or group acting in concert with, or which controls, is controlled by, or under common control with, that shareholder.

        Subchapter 25E (relating to control transactions) provides generally that if any person or group acquires 20% or more of the voting power of a publicly traded corporation, notice must be given to the



other shareholders, who then may demand from such person or group the fair value of their shares, including a proportionate amount of any control premium.

        Subchapter 25F (relating to business combinations) restricts the ability of a person who becomes an "interested shareholder" to enter into certain "business combinations" with the corporation for a period of five years, unless one of certain exceptions apply. The term "business combination" is defined broadly to include various transactions including mergers, consolidations, asset sales and other similar transactions. An "interested shareholder" is defined generally as the beneficial owner of at least 20% of a corporation's voting stock.

        Subchapter 25G (relating to control-share acquisitions) provides that a person who acquires for the first time 20% or more, 331/3% or more, or 50% or more of a company's voting shares shall not have any voting rights unless the disinterested shareholders approve such voting rights. If this approval is not obtained, the corporation may force the shareholder to sell his or her shares to the corporation.

        Subchapter 25H (relating to disgorgement) applies in the event that (1) any person or group publicly discloses that such person or group may acquire control of the corporation through any means or (2) a person or group acquires, or publicly discloses an offer or intent to acquire, 20% or more of the voting power of the corporation. Any profits from sales of equity securities of the corporation by such person or group during a period of 18 months subsequent to obtaining the status of a controlling person revert to the corporation if the securities sold were acquired during such 18 month period or within 24 months prior thereto.

        Subchapters 25D through 25J contain a wide variety of exemptions, exclusions and safe harbors. Subchapters I and J (relating to severance compensation for terminated employees and labor contracts) apply to certain acquisitions of shares and business combinations. In such cases, terminated employees may be entitled to severance payments and labor contracts may be given protection against termination. A Pennsylvania corporation may opt out of any of these provisions. Only subchapters 25D and 25F are applicable to Iron Mountain PA; the Pennsylvania Charter provides that subchapters 25E, 25G and 25H shall not be applicable to Iron Mountain PA and subchapters 25I and 25J are nullified by opting out of subchapter 25G.

Factors a Board May Consider in Exercising its Fiduciary Duties

        Delaware law does not contain any statutory provision permitting the board of directors, committees of the board or individual directors, when discharging their duties, to consider, and it is therefore unclear under current Delaware law whether the board of directors, committees of the board or individual directors may consider, the interests of any constituencies other than the corporation or its stockholders.

        The PaBCL, on the other hand, provides that in discharging their duties, the board of directors, committees of the board and individual directors may, in considering what is in the best interests of the corporation, consider, to the extent they deem appropriate, all pertinent factors, including the following:


Dividend Rights

        Under the DGCL, directors may, subject to any restrictions in a corporation's certificate of incorporation, declare and pay dividends either (1) out of its surplus or (2) if no surplus exists, out of its net profits, for the current fiscal year and/or the preceding fiscal year. The directors of a Delaware corporation may not declare dividends out of net profits, however, if the capital of the corporation is less than the aggregate amount of capital represented by the issued and outstanding stock of all classes having a preference upon the distribution of assets. The rights of stockholders of a Delaware corporation to receive dividends are subject to the rights and preferences of holders of future series of preferred stock with preferential dividend rights, if any. Iron Mountain PA is authorized to issue shallup to 10 million shares of Preferred Stock, but no Preferred Stock is issued and outstanding. Iron Mountain DE will similarly be set forth in its Articles of Incorporation. The Company's Amended and Restated Articles of Incorporation (the "Restated Articles") presently authorize the Companyauthorized to issue 150,000,000 shares of Common Stock and 10,000,00010 million shares of Preferred Stock.

        AsUnder the PaBCL, a corporation is prohibited from making a distribution to its shareholders if, after giving effect to the distribution (1) the corporation would be unable to pay its debts as they become due in the usual course of April 1, 2004, 85,841,854business, or (2) the corporation's total assets would be less than the sum of its total liabilities plus the amount that would be needed upon the dissolution of the authorizedcorporation to satisfy the rights, if any, of shareholders having superior preferential rights to the shareholders receiving the distribution.

        Like the Pennsylvania Charter, the Delaware Charter contains no restrictions regarding dividends.

Stock Redemptions and Repurchases

        Under the DGCL, a corporation may not purchase or redeem its own shares when the capital of the corporation is impaired or when such purchase or redemption would cause an impairment of the capital of the corporation. A Delaware corporation may, however, purchase or redeem any of its preferred shares if such shares will then be retired and the capital of the corporation is reduced in accordance with the DGCL. The PaBCL permits a corporation to redeem any and all classes of its shares and treats such redemption or repurchase like a dividend by the corporation to or for the benefit of its shareholders, subject to the same limitations described above under the caption "—Dividend Rights".

Voting Rights

        Although the DGCL permits cumulative voting, the Delaware Charter does not provide for cumulative voting in the election of directors. Pursuant to the Delaware Charter and Delaware Bylaws, holders of Iron Mountain DE common stock are entitled to one vote per share on all matters voted on by stockholders.

        The PaBCL grants cumulative voting rights to shareholders but allows an exception if the charter so provides. In the case of Iron Mountain PA, the Pennsylvania Charter prohibits cumulative voting in the election of directors. Pursuant to the PaBCL, holders of the Common Stock andare entitled to one vote per share on all matters voted on by shareholders.

Shareholder Meetings

        Under the DGCL, if there is a failure to hold the annual meeting or to take action by written consent to elect directors in lieu of an annual meeting for a period of 30 days after the designated date for the annual meeting, or if no sharesdate has been designated for a period of Preferred Stock were issued and outstanding.13 months after the latest to occur of the organization of the corporation, its last annual meeting or the last action by written consent to elect directors in lieu of an annual meeting, the Court of Chancery may summarily order a meeting to be held upon the request of any stockholder or director. Under the DGCL, a special meeting of the stockholders may be called by a corporation's board of directors or any other person as



may be authorized by a corporation's certificate of incorporation or bylaws. Like the Pennsylvania Bylaws, the Delaware Bylaws provide that special meetings of the stockholders may be called only by the chairman of the board or by the board of directors of Iron Mountain DE.

        Under the PaBCL, if the annual meeting for the election of directors is not held within six months after the date designated for the annual meeting pursuant to the bylaws, any shareholder may call the meeting at any time thereafter. Pursuant to the PaBCL, special meetings of shareholders may be called by the board of directors or by any officer or by any other persons as provided in the bylaws. The Board has unanimously approved, and unanimously recommendsPaBCL provides that the shareholders of a publicly traded corporation do not have a statutory right to call a special meeting. The Pennsylvania Bylaws do not provide an affirmative right to shareholders to call a special meeting.

Action by Shareholders Without a Meeting

        Although Delaware law permits stockholder action to be taken by written consent, the Company approve,Delaware Charter specifically prohibits action by written consent of stockholders. Similarly, Pennsylvania law permits shareholder action by consent, but the Pennsylvania Bylaws prohibit action by either unanimous or partial consent of shareholders.

Shareholder Proposals, Nominations and Rights to Elect Directors

        The DGCL and the PaBCL do not include provisions restricting the manner in which nominations for directors may be made by stockholders or the manner in which business may be brought before a proposalmeeting.

        The Pennsylvania Bylaws provide that nominations of persons for election to the Board may be made only by the Board, a committee of the Board or by any shareholder who complies with the notice provisions in the Pennsylvania Bylaws. Notice must be given by a shareholder of a nomination, in writing:

        The Pennsylvania Bylaws similarly restrict the right of shareholders to bring business before a meeting of shareholders by requiring advance notice to the corporation of the general nature of the business the shareholder seeks to bring before the meeting.

        The Delaware Bylaws contains substantially similar provisions.

Charter Amendments

        Under the DGCL, an amendment or change to the certificate of incorporation generally requires the approval of the board of directors, followed by the approval of the holders of a majority of the shares entitled to vote, unless the certificate of incorporation increases the required vote. The Delaware Charter does not require a greater percentage vote.

        Under the PaBCL, an amendment to the articles of incorporation requires the approval of the board of directors followed by the affirmative vote of a majority of the votes actually cast by all shareholders entitled to vote thereon at a meeting at which a quorum is present and, if any class or



series of shares is entitled to vote thereon as a class, the affirmative vote of a majority of the votes cast in each such class vote. Under the PaBCL, the shareholders of a publicly traded corporation are not entitled by statute to propose an amendment to the articles of incorporation.

Amendments to Bylaws

        Under the DGCL, bylaws may be adopted, amended or repealed by a vote of a majority of the stockholders entitled to vote thereon. Delaware law also allows for a majority of the board of directors to make changes to the corporation's bylaws if the certificate of incorporation confers this power upon the directors. The Delaware Charter will grant this power to directors. The power vested in the stockholders is not, however, divested or limited because the board of directors also has such power.

        Under the PaBCL, bylaws may be adopted, amended and repealed by a vote of a majority of the votes actually cast by all shareholders entitled to vote thereon, and, if any shareholders are entitled to vote as a class, the affirmative vote of the majority of votes cast by such class. This authority may be expressly vested in the board of directors by the bylaws, subject to the power of the shareholders to change such action, unless the subject of the amendment is solely within the province of the shareholders. The Pennsylvania Bylaws provide that the Pennsylvania Bylaws may be amended or repealed by the vote of a majority of all directors, except for amendments that are solely within the province of the shareholders, in which case the affirmative vote of a majority of the votes cast by all shareholders entitled to vote is required to amend or repeal the first sentencebylaws.

Mergers and Fundamental Corporate Transactions

        Under the DGCL, fundamental corporate transactions, such as mergers, consolidations, sales of Article FOURTHall or substantially all of a corporation's assets and dissolutions, require the approval of a majority of the Restated Articlesboard of directors and approval of the holders of a majority of the shares of a corporation's common stock. Although the DGCL permits a corporation to increase the numberminimum percentage vote required, the Delaware Charter and Delaware Bylaws do not require a greater vote.

        Under the PaBCL, fundamental corporate transactions, such as mergers, consolidations, the sale, lease, exchange or other disposition of all, or substantially all, of the property and assets of a corporation and dissolutions, require board approval and approval by a majority of the votes actually cast by the shareholders entitled to vote thereon, and, if shareholders are entitled to vote as a class, the affirmative vote of the majority of votes cast by such class. Although the PaBCL permits a corporation to increase the minimum percentage vote required, the Pennsylvania Charter and Pennsylvania Bylaws do not increase the vote.

Dissenters' Rights of Appraisal

        Under the DGCL, unless the certificate of incorporation of a corporation provides otherwise, there are no appraisal rights in connection with a merger or consolidation to holders of shares that are listed on a national securities exchange, quoted on a national market system or held of Common Stock thatrecord by more than 2,000 stockholders unless the Company is authorizedplan of merger or consolidation requires the stockholders to issue from 150,000,000 to 200,000,000 shares. The full textaccept anything other than stock of the first sentencesurviving corporation or stock of Article FOURTHanother corporation that is listed on a national securities exchange, quoted on a national market system or held of record by more than 2,000 stockholders, cash in lieu of fractional shares or any combination of the Articlesforegoing. In addition, the DGCL denies appraisal rights to the stockholders of Incorporation as proposedthe surviving corporation in a merger if that merger did not require for its approval the vote of the stockholders of the surviving corporation. The Delaware Charter does not provide for additional appraisal rights.

        The PaBCL generally does not provide for dissenters' rights to be amended by this proposal is as follows: "FOURTH: The aggregate numberholders of shares which the corporation shall have authority to issue is Two Hundred Ten Million (210,000,000) shares, to be divided into Two Hundred Million (200,000,000) sharesthat are listed on a national securities exchange or held beneficially or of Common Stock, par value $0.01 per share and Ten Million (10,000,000) shares of Preferred Stock, par value $0.01 per share."record by more than 2,000 shareholders.



Reasons for and General Effect of the Proposed AmendmentFederal Income Tax Consequences

        The BoardReincorporation will qualify for federal income tax purposes as a tax free reorganization under section 368(a) of Directors believesthe Code. As a condition to the closing of the Reincorporation, Iron Mountain DE will receive an opinion from Sullivan & Worcester LLP to the effect that, on the basis of the existing provisions of the Code, U.S. Treasury regulations issued thereunder, current administrative rules, pronouncements and court decisions, for federal income tax purposes upon completion of the Reincorporation:

        (1)   The Reincorporation will constitute a "reorganization" within the meaning of section 368(a)(1)(F) of the Code, and Iron Mountain PA and Iron Mountain DE will each be a "party to a reorganization" within the meaning of section 368(b) of the Code;

        (2)   No gain or loss will be recognized by Iron Mountain PA's shareholders upon the exchange (whether actual or constructive) of their shares of Iron Mountain PA for shares of Iron Mountain DE in the Reincorporation; and

        (3)   The aggregate tax basis of the shares of Iron Mountain DE received (whether actually or constructively) by each shareholder of Iron Mountain PA pursuant to the Reincorporation will be the same as the aggregate tax basis of the shares of Iron Mountain PA held by such shareholder immediately prior to the Reincorporation, and the holding period of the shares of Iron Mountain DE received (whether actively or constructively) by each shareholder of Iron Mountain PA will include the period during which the shares of Iron Mountain PA surrendered therefor were held by such shareholder (provided that the current level of authorized shares of Common Stock may restrictIron Mountain PA were held as a capital asset on the Company's abilitydate of the Reincorporation).

        Opinions of counsel are not binding upon the Internal Revenue Service (the "IRS") or the courts. The Company has not requested a ruling from the IRS with respect to issue or reserve Common Stock for general corporate purposes. The purposethe federal income tax consequences of the Reincorporation under the Code. Shareholders of Iron Mountain PA should consult their tax advisors regarding the effect, if any, of the proposed amendment is to provide sufficient authorized sharesReincorporation in light of Common Stock to givetheir individual circumstances. In particular, because the Board the flexibility to issue Common Stock in the future in connection with stock dividends, acquisitions and other transactions that management believes would provide the potential for growth and for other general corporate purposes. If the proposed amendment is adopted, there will be 114,158,146 shares of Common Stock authorized and unissued, based on the number of shares outstanding and reserved as of April 1, 2004.

        No further action or authorization by the Company's shareholders would be necessary priorabove discussion relates only to the issuance of additional shares of Common Stock, except as may be required for a particular transaction by applicable law or regulatory agencies or by the rulesU.S. federal income tax consequences of the NYSE orReincorporation, shareholders of Iron Mountain PA should also consult their tax advisors as to the foreign, state and local tax consequences, if any, other stock exchange on which the Company's securities may then be listed. If additional shares are available, transactions dependent upon the issuance of additional shares would be less likely to be impeded or undermined by delays and uncertainties occasioned by the need to obtain prior shareholder authorization. The ability to issue shares, as deemed in the Company's best interests by the Board, may also permit the Company to avoid expenses incurred in holding special shareholders' meetings in the future.

        At the present time, the Board has no specific plans to issue or reserve additional shares of Common Stock other than in connection with routine grants under the 2002 Stock Incentive Plan or any similar replacement plan and issuances of shares under the ESPP. Shareholders of the Company have no preemptive rights with respect to any shares of the Company's Common Stock.

Certain Effects of the Proposed Amendment

        The issuance of additional shares of Common Stock by the Company could have an antitakeover effect by making it more difficult to obtain shareholder approval of various actions, such as a merger or removal of management. Additionally, the issuance of additional shares of Common Stock by the Company could have the effect of diluting existing shareholder earnings per share, book value per share and voting power. The amendment to the Restated Articles, if approved, could strengthen the

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position of management and might make the removal of management more difficult, even if removal would be generally beneficial to the Company's shareholders. The authorization to issue the additional shares of Common Stock would provide management with a capacity to counter the efforts of unfriendly tender offerors by issuing securities to others who are friendly or desirable to management. However, the submission of the proposed amendment to the Restated Articles is not a part of any present plan by the Company's management to adopt a series of amendments to the Company's Articles of Incorporation or Bylaws so as to render the takeover of the Company more difficult.

        The proposed amendment to the Restated Articles is not the result of management's knowledge of any specific effort to accumulate the Company's securities or to obtain control of the Company by means of a merger, tender offer, proxy solicitation in opposition to management or otherwise.Reincorporation.

Required Vote

        The affirmative vote of the holders of a majority of the votes properly cast at the Annual Meeting on the proposal is required to approve the amendment toMerger Agreement and the Company's Restated Articles.Reincorporation, which will also constitute approval of the Delaware Charter and the Delaware Bylaws. For purposes of determining whether a majority of the votes have been cast in favor of the approval of the amendment toMerger Agreement and the Company's Restated Articles,Reincorporation, only those cast "For" or "Against" are included, and any abstentions orand broker non-votes will not count in making that determination.

        The Board recommends that you vote FOR the proposal to amendapproval of the Company's Restated Articles to increaseMerger Agreement and the number of authorized shares of Common Stock from 150,000,000 to 200,000,000.Reincorporation.

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ITEM 3

APPROVAL OF AMENDMENT TO THE IRON MOUNTAIN INCORPORATEDCOMPANY'S
20022003 EMPLOYEE STOCK INCENTIVEPURCHASE PLAN

        The Company's Board has unanimously approved, and unanimously recommends that the shareholders of the Company approve, an amendment to the 20022003 Employee Stock IncentivePurchase Plan (the "ESPP"), attached hereto as Appendix B,D, to increase the number of shares of Common Stock authorized for issuance under the 2002 Stock Incentive PlanESPP from 1,352,5431,125,000 to 3,352,543.2,325,000.

        The Board believes that equity interests areequity-based compensation is a significant factor in the Company's ability to attract, retain and motivate keyits employees, directors and other service providers thatwho are critical to the Company's long-term success and that an increase in the number of shares available for issuance under the 2002 Stock Incentive PlanESPP is necessary in order to provide those persons with incentives to serve the Company. In approving the increase in the number of shares reserved for issuance under the 2002 Stock Incentive Plan,ESPP, the Board consideredtook into consideration the shares projected to be available under the ESPP as of the close of the current offering on May 31, 2005. As of that date, it is projected that no more than 445,586 shares will be available. Since at present no more than 195,000 shares are available in any six-month offering period, sufficient shares remain to complete only approximately 550,000two additional offerings (ending November 30, 2005 and May 31, 2006 respectively). Under current offering period limitations, the increase in shares wereavailable by 1,200,000 is designed to ensure that a sufficient number of shares are available for grant under the 2002 Stock Incentive Plan as of April 1, 2004, the average annual rate of grants during 2001 through 2003, and the portion of the Company's outstanding shares represented by shares subject to options, relative to other publicly held companies in related businesses.an additional three years.

        The following summary of the material features of the 2002 Stock Incentive PlanESPP is qualified in its entirety by reference to the complete text of the 2002 Stock Incentive Plan, which is filedESPP, attached hereto as an appendix to the Company's Proxy Statement on Schedule 14A filed in April 2002.Appendix E.

        Overview.    The 2002 Stock Incentive Plan permits the issuanceESPP operates by granting, in a series of equity-based awards, including incentive stockofferings, options nonqualified stock options, grants of Common Stock, whether or not subject to restrictions, and stock appreciation rights. The 2002 Stock Incentive Plan initially reserved 1,352,543 shares ofacquire Common Stock. If shareholders approveThe Compensation Committee determines the amendment tocommencement date and duration of offerings. The Compensation Committee may also, and currently does, limit the 2002 Stock Incentive Plan, the totalmaximum amount of Common Stock reservedavailable with respect to an offering.

        In general, offerings last for six months and begin each June 1 and December 1. During an offering, payroll deductions are accumulated on behalf of each participant. At the end of the offering, the options are exercised and the accumulated payroll deductions are retained by the Company as full payment of the option price. Each participant receives a number of shares of Common Stock equal to the accumulated payroll deductions credited to the participant's account as of the exercise date divided by the option price. The "option price" of shares of Common Stock will be 3,352,543.85% of the lower of the fair market value of Common Stock at the start of the offering or on the exercise date. Fair market value under the ESPP generally means the average of the highest and lowest sale price of Common Stock on the date in question. The Compensation Committee may, with respect to a future offering, reduce (or eliminate) the option price discount or apply any discount only to the fair market value of the shares on the exercise date.

        Purpose, Eligible Individuals, Effective Date and Duration.Shares Available under the ESPP.    The 2002 Stock Incentive Plan was effectiveAs of April 1, 2002.2005, there were approximately 445,586 shares available for future sale under the ESPP. The purposeproposed amendment to the ESPP will increase the total number of shares that may be subject to options under the ESPP by 1,200,000.

        If an option expires or is terminated or surrendered, the shares allocable to the option may again be available under the ESPP. If at the end of an offering there are not enough shares available to satisfy all desired purchases, a pro rata allocation of the 2002 Stock Incentive Plan isavailable shares will be made among all participants, and any excess payroll deductions will be returned to encourage employees, officers, directorsparticipants.

        Eligibility and consultantsParticipation.    In general, any employee of the Company and our subsidiariesor a subsidiary that is (or is treated for federal income tax purposes as) a corporation who render servicesis customarily employed for more than



five months in a calendar year may become a participant in any future offering under the ESPP by electing to our management, development or operationparticipate prior to continue their association with us by providing favorable opportunities for themthe commencement of the offering. However, the following persons are ineligible to participate in the ownership of our Common Stock and in our future growth through grants of our Common Stock, with or without restrictions, options to acquire our Common Stock and other rights to compensation in amounts determined by the value of our Common Stock (collectively, "Awards"). For this purpose, subsidiaries include corporations, companies, partnerships and other forms of business organizations in which we ownESPP: (1) any employee who owns, directly or indirectly, 50%as of the start of an offering, 5% or more of the Company's stock or the stock of one of the Company's corporate subsidiaries; (2) any employee of a subsidiary that does not elect to participate in the ESPP; (3) any union employee, if the union elects not to participate in the ESPP; (4) any individual who is not an employee, including outside directors, consultants and independent contractors; and (5) any employee hired fewer than six months prior to the commencement of an offering. In addition, an employee will not be granted an option that would permit him or her to own (or be considered to own) or hold outstanding options to purchase 5% or more of the total combined voting power or value of all classes ofthe Company's stock or other formthe stock of equity ownershipone of the Company's corporate subsidiaries, and a participant cannot acquire in any year more than $25,000 worth of the Company's stock under the ESPP (based on the value of the Company's stock at the start of the offering).

        A participant may authorize payroll deductions of from 1% to 15% of the participant's cash compensation on each pay date. A participant can decrease his or in which we have a significant financial interest. The recipienther rate of payroll deductions, but the participant can never increase the rate of payroll deductions once an offering begins.

        A participant may, prior to the end of an Award is referred tooffering period, and at such time and in such manner as the Compensation Committee may prescribe, withdraw from an "Optionee." At this time, approximately 13,000 persons are eligible to receive options pursuantoffering and request payment of an amount in cash equal to the 2002 Stock Incentive Plan.

        The 2002 Stock Incentive Planaccumulated payroll deductions credited to the participant's account under the ESPP. In no event will terminate on March 31, 2012, unless earlier terminated by the Board. Termination of the 2002 Stock Incentive Plan will not affect Awards made priora participant receive interest with respect to termination, but no Awards will be made after termination.his or her payroll deductions, whether used to exercise options or returned in cash.

        Shares SubjectTermination of Employment.    Upon termination of employment for any reason other than death, the participant will receive a payment in cash of the amount credited to the 2002 Stock Incentive Plan.    The total number of shares of our Common Stock that may be subject to Awardsparticipant's account under the 2002 Stock Incentive Plan may not exceed 1,352,543 shares, or 3,352,543 shares if the amendment is approved. The shares may be authorized but unissued shares or treasury shares. The total amount of Common Stock that may be granted under the Plan to any single person in any calendar year may not exceed in the aggregate 500,000 shares. To the extent that

14



an option or other form of Award lapses or is forfeited, the shares subject to the Award will again become available for grant under the terms of the 2002 Stock Incentive Plan.

ESPP. In the event that a participant dies prior to the end of any change inan offering period, the number of shares or kind of Common Stock outstanding pursuant to a reorganization, recapitalization, exchange of shares, stock dividend or split or combination of shares, appropriate adjustmentsparticipant's account will be madepaid in cash to the numberhis or her estate.

        Restrictions on Transfer.    A participant may not transfer, assign, pledge or otherwise dispose of shares of authorized Common Stock, to the number of shares of Common Stock subject to outstanding Awards, to the exercise price per share of options and other forms of Awards and to the kind of shares that may bean option issued under the 2002 Stock Incentive Plan.

        As of April 1, 2004, 785,064 options to purchase shares of Common Stock were outstandingESPP. Shares acquired under the 2002 Stock Incentive Plan.ESPP at the end of an offering period will be freely tradable, subject in all cases to the participant's compliance with applicable laws and the Company's Statement of Insider Trading Policy.

        Administration.    AlthoughThe ESPP became effective April 7, 2003 and is administered by the BoardCompensation Committee. The Compensation Committee has the authority to administer the Plan, it has generally delegated this authority to the Incentive Plan Subcommittee, which administers all of our equity-based compensation plans. Each member of the Incentive Plan Subcommittee is a "non-employee director" within the meaning of Rule 16b-3 promulgated under the Exchange Actadopt, amend and an "outside director" within the meaning of Section 162(m) of the Code.

        Subject to the terms of the 2002 Stock Incentive Plan, the Incentive Plan Subcommittee has the authority to: (1) select Optionees; (2) determine the terms and conditions of Awards, including the price to be paid by an Optionee for any Common Stock; and (3) interpret the 2002 Stock Incentive Plan and prescriberescind such rules and regulations foras, in its administration.opinion, may be advisable in the administration of the ESPP and to decide all questions of interpretation and application of such rules and regulations, which decision will be final and binding.

        Stock Options.Forfeiture for Dishonesty.    The Incentive Plan Subcommittee may grant incentive stock optionsIf the Board determines that a participant has engaged in fraud, embezzlement, theft, commission of a felony or proven dishonesty in the course of his or her employment that has damaged the Company or a subsidiary or has disclosed trade secrets or other proprietary information of the Company or a subsidiary, (1) the individual's participation in the ESPP will terminate and nonqualified stock options under the 2002participant will forfeit his or her right to receive any Common Stock Incentive Plan. The Incentive Plan Subcommittee determinesthat has not been delivered pursuant to an offering and (2) the numberCompany will have the right to repurchase all or any part of the shares of Common Stock subject to each option, its exercise price, its duration and the manner and time of exercise. Incentive stock options may be issued only to employees of the Company or of a corporate subsidiary of ours, and the exercise price must be at least equal to the fair market value of the Common Stock as of the date the option is granted. Further, an incentive stock option generally must be exercised within ten years of grant. The Incentive Plan Subcommittee, in its discretion, may provide that any option is subject to vesting limitations that make it exercisable during its entire duration or during any lesser period of time.

        The exercise price of an option may be paid in cash, in shares of Common Stock ownedacquired by the Optionee, by delivery of a recourse promissory note secured byparticipant upon the Common Stock acquired upon exercise of the option (provided that such a loan would not be available to any executive officer or director of the Company) or by means of a "cashless exercise" procedure in which a broker transmits to us the exercise price in cash, either as a margin loan or against the Optionee's notice of exercise and confirmation by us that we will issue and deliver to the broker stock certificates for that number of shares of Common Stock having an aggregate fair market value equal to the exercise price, or agrees to pay the exercise price to us in cash upon its receipt of stock certificates.

        In its discretion, and subject to the terms of the 2002 Stock Incentive Plan, the Incentive Plan Subcommittee may grant a reload option to purchase the number of shares of Common Stock delivered to us in full or partial payment of the exercise price on theearlier exercise of any option or in full or partial payment ofpursuant to the tax withholding obligations resulting from the exercise of any option.

        Options are,ESPP, at the discretion of the Incentive Plan Subcommittee, transferable to members of the Optionee's immediate family or to a family partnership or trust for the benefit of the Optionee's immediate family.

        Stock Appreciation Rights.    The Incentive Plan Subcommittee may also grant stock appreciation rights to Optionees on such terms and conditions as it may determine. Stock appreciation rights may be granted separately or in connection with an option. Upon the exercise of a stock appreciation right, the

15



Optionee is entitled to receive paymentprice equal to the excess of the fair market value, on the date of exercise, of the number of shares of Common Stock for which the stock appreciation right is exercised, over the exercise price for the Common Stock under a related option, or if there is not a related option, over an amount per share stated in the agreement setting forth the terms and conditions of the stock appreciation right. Payment may be made in cash or other property, including Common Stock, in accordance with the provisions of the applicable agreement. Upon the exercise of a stock appreciation right related to an option, the option will terminate aspaid to the number of shares of Common Stock for which the stock appreciation right is exercised.

        Stock Grants.    The Incentive Plan Subcommittee may issue shares of Common Stock to Optionees, eitherCompany upon exercise, together with or without restrictions, as determined by it in its discretion. Restrictions may include conditions that require the Optionee to forfeit the shares in the event that the holder ceases to provide services to us or one of our subsidiaries before a stated time. Unlike holders of options and stock appreciation rights, the recipient of a stock grant, including a stock grant subject to restrictions, unless otherwise provided for in a restricted stock agreement, has the rights of a shareholder of ours to vote and to receive payment of dividends on the Common Stock.

        Special Bonus Award.    The Incentive Plan Subcommittee may grant in connection with any nonqualified stock option or stock grant a special cash bonus in an amount not to exceed the lesser of (1) the combined federal, state and local income and employment tax liability incurred by the Optionee as a consequence of acquiring Common Stock on the exercise of the option or the grant or vesting of Common Stock, and the related special bonus, or (2) 30% of the imputed income realized by the Optionee on account of the exercise or vesting, and the related special bonus. A grant may also provide that the Company will lend an Optionee an amount not more than the amount described in the preceding sentence, less the amount of any special cash bonus.interest.

        Effect of Certain Corporate Transactions.Changes.    If, while unexercised Awards remain outstanding underbefore an offering closes, the 2002 Stock Incentive Plan we mergeCompany merges or consolidateconsolidates with one or more corporations (whether or not we arethe Company is the surviving corporation), if we areor the Company is liquidated, or sellsells or otherwise disposedisposes of substantially all of ourits assets to another entity, or if there is a "change in control"of control," then except as otherwise specifically provided to the contrary in any applicable agreement, the Incentive Plan Subcommittee mayCompensation Committee, in its discretion, amend the terms of all unexercised Awards so that may



either: (1) convert outstanding options such that after the effective date of the event, each Optioneeparticipant is entitled upon exercise of an Award, to receive, in lieu of Common Stock, the number and class of shares of suchthe stock or other securities to which he or shethe participant would have been entitled had he or shethe participant been a shareholder at the time of the event,event; or is entitled to receive from(2) end the successor entity a new Awardoffering and exercise the options as of comparable value; (2) each Optionee is given an opportunity to exercise all or some of his or her unexercised Awards during a twentythe day period ending with the event, at which time the unexercised Awards will be cancelled; or (3) all unexercised Awards are cancelled as ofbefore the effective date of the event in consideration for cash or other consideration with a value equal to the valueevent.

        A "change of the shares the Optionee would have received had the Award been exercised (to the extent exercisable). In addition to the foregoing, the Incentive Plan Subcommittee may in its discretion also amend the terms of an Award by cancelling some or all of the restrictions on its exercise to permit its exercise to a greater extent than that permitted under its existing terms.

        For these purposes, a change of control willcontrol" shall be deemed to have occurred if any person (as thatsuch term is used in Section 13(d) and 14(d)(2) of the Exchange Act) other than a trust related to anyan employee benefit plan maintained by the Company becomes the beneficial owner (within the meaning of Rule 13d-3 under the Exchange Act) of 50% or more of our outstanding Common Stock, and within the period of 24 consecutive months immediately thereafter, individuals other than (1) individuals who at the beginning of such period constitute the entire Board or (2) individuals whose election, or nomination for election by the Company's shareholders, was approved by a vote of at least two-thirds of the directors then still in office who were directors at the beginning of the period, become a majority of the Board.

16        If the Reincorporation described in Item 2 takes place, all employee benefit, stock option and employee stock purchase plans of Iron Mountain PA will become Iron Mountain DE plans, and each option or right issued by such plans will automatically be converted into an option or right to purchase the same number of shares of Iron Mountain DE common stock, at the same price per share, upon the same terms and subject to the same conditions, as set forth in Item 2 above.



        Amendments toAmendment or Termination of the 2002 Stock Incentive Plan.ESPP.    The Board may modify, revise or terminate the 2002 Stock Incentive Plan at any time, andwithout a vote by shareholders, terminate or, from time to time, exceptamend, modify or suspend the ESPP; provided, however, that without shareholder approval of our shareholders is required with respect to any amendment tothere will be no: (1) change in the aggregate number of shares of Common Stock that may be issued under the 2002 Stock Incentive Plan or to any personESPP; (2) change in a year, change the class of persons eligible to receive Awardsparticipate in the ESPP; or make any(3) other changeschange to the ESPP that requirerequires shareholder approval under applicable law. Amendments adversely affecting outstanding Awards may notUnless terminated earlier, the ESPP will terminate on the date on which there are no longer any shares of Common Stock available to be made without the consent of the holder of the Award.offered.

        The Board may also amend the 2002 Stock Incentive Plan as necessary to enable awards to qualify for favorable foreign tax treatment in the case of an Optionee who is subject to a tax regime outside the United States.

Tax Treatment.The following description of the federal income tax consequences of Awardsthe ESPP is general and does not purport to be complete. In addition, the description does not discuss the tax consequences arising as a result of the participant's death or of the tax consequences of the ESPP under the laws of any state or foreign country in which the participant may reside.

        Federal Income Tax TreatmentConsequences of Options.the ESPP.    An Optionee realizes no taxable income when a nonqualifiedThe ESPP is intended to constitute an "employee stock option is granted. Instead, the difference between the fair market valuepurchase plan" under Section 423 of the Common Stock acquired pursuant toCode. As presently in effect, under Section 423 of the Code, a participant will not realize income as a result of either the grant of an option at the start of an offering period or the exercise of an option at the end of an offering period and the Company will not be entitled to an income tax deduction at such grant date or exercise price paid is taxed as ordinary compensation income whendate. If the option is exercised. The difference is measured and taxed asparticipant does not dispose of the datestock acquired under the ESPP before the earlier of exercise, iftwo years after the Common Stock is not subject to a "substantial riskstart of an offering or forfeiture," or asone year after the end of the date or dates on which the risk terminates in other cases. An Optionee may elect to be taxed on the difference between the exercise price and the fair market value of the Common Stock on the date of exercise, even though some or all of the Common Stock acquired is subject to a substantial risk of forfeiture. Gain onan offering, then upon the subsequent sale of the Common Stock acquired by exercise ofstock, the option is taxed as capital gain. We receive no tax deduction on the grant of a nonqualified stock option, but we are entitled to a tax deduction when the Optionee recognizesparticipant will have ordinary compensation income on or after exercise of the option, in the same amount as the income recognized by the Optionee.

        Generally, an Optionee incurs no federal income tax liability on either the grant or the exerciselesser of an incentive stock option, although an Optionee will generally have taxable income for alternative minimum tax purposes at the time of exercise equal to the excess15% of the fair market value of the Common Stock subjectstock as of the start of the offering or the excess, if any, of the selling price of the stock over the option price. Any additional gain or loss will be treated as long-term capital gain or loss. The Company is not entitled to an income tax deduction with respect to the option overordinary compensation income described above.

        If the exercise price. Provided thatparticipant disposes of the Common Stock is held for at leaststock acquired under the ESPP before the earlier of two years after the start of the offering or one year after the date of exerciseend of the option and at least two years after its date of grant, any gain realized on a subsequent sale of the Common Stock will be taxed as long-term capital gain. If the Common Stock is disposed of within a shorter period of time, the Optionee will recognize ordinary compensation income in an amount equal to the difference between the sales price and the exercise price or (if less) the difference between the fair market value at the time of exercise and the exercise price. We receive no tax deduction on the grant or exercise of an incentive stock option, but we are entitled to a tax deduction if the Optionee recognizes ordinary compensation income on account of a premature disposition of shares acquired on exercise of an incentive stock option, in the same amount and at the same time as the Optionee recognizes income.

        Tax Treatment of Stock Appreciation Rights.    An Optionee recognizes no income upon the grant of a stock appreciation right, but upon its exercise realizes ordinary compensation income in an amount equal to the cash or cash equivalent that he receives at that time. If the Optionee receives Common Stock upon exercise of the stock appreciation right, he recognizes ordinary compensation income measured by the fair market value of the Common Stock so received (or, if the Common Stock is subject to a substantial risk of forfeiture, at the date or dates on which the risk expires, unless he or she elects to be taxed currently). We are entitled to a tax deduction in the amount of ordinary compensation income recognized.

        Tax Treatment of Stock Grants.    A person who receives a stock grant without any restrictions will recognize ordinary compensation income on the fair market value of the Common Stock over the

17



amount (if any) paid for the Common Stock. If the Common Stock is subject to restrictions, the recipient generally will not recognize ordinary compensation income at the time the award is received, but will recognize ordinary compensation income when restrictions constituting a substantial risk of forfeiture lapse. The amount of such income will be equal tooffering, then the excess, of the aggregate fair market value, as of the date the restrictions lapse, over the amount (if any) paid for the Common Stock. Alternatively, the Optionee may elect to be taxed, pursuant to Section 83(b) of the Code, on the excessif any, of the fair market value of the Common Stockstock at the timeend of grantthe offering over the amount (if any) paid for the Common Stock, notwithstanding any restrictions. All such taxable amounts are deductible by us at the time and in the amount of theoption price will be ordinary compensation income recognized by the Optionee.

        Section 162(m) of the Code.    Section 162(m) of the Code generally disallows an income tax deduction to public companies for compensation in excess of $1,000,000 paid in any year to the chief executive officer and any of the four most highly compensated other executive officers, to the extent that this compensation is not "performance based" within the meaning of Section 162(m) of the Code. In the case of a stock plan, the performance-based exception is satisfied if, in addition to other requirements, the plan, including the amount of stock available for grant under the plan, is approved by shareholders, the grants are made by a committee of outside directors,participant, and the amount of compensation a person can receive is based solely on an increase in the value of the Common Stock after grant. If the amendment to increase the number of shares available for grant under the 2002 Stock Incentive Plan is approved by shareholders, one of the requirements for the performance-based exceptionCompany will be satisfiedentitled to a deduction with respect to shares awarded underthat income. Any additional gain or loss will be treated as short-term or long-term capital gain or loss, depending on the Plan.holding period.



        The affirmative vote of holders of a majority of the votes properly cast at the Annual Meeting is required to approve the amendment to the 2002 Stock Incentive PlanESPP to increase the number of shares of Common Stock issuable thereunder from 1,352,5431,125,000 to 3,352,543.2,325,000. For purposes of determining whether a majority of the votes have been cast in favor of the approval of the amendment to the 2002 Stock Incentive Plan,ESPP, only those cast "For" or "Against" are included, and any abstentions or broker non-votes will not count in making that determination. Additionally, NYSE rules require that at least a majority of the votes that all shareholders are entitled to cast at the Annual Meeting must vote on the Plan Amendment, whether for or against.

        The Board recommends that you vote FOR the approval of the amendment to the 20022003 Employee Stock IncentivePurchase Plan.


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ITEM 4


RATIFICATION OF SELECTION OF INDEPENDENT PUBLIC ACCOUNTANTS

        Subject to ratification by the shareholders, the Audit Committee has selected the firm of Deloitte & Touche LLP as the Company's independent public accountants for the current year.

        Representatives of Deloitte & Touche LLP are expected to be present at the Annual Meeting. They will have the opportunity to make a statement if they desire to do so and will be available to respond to appropriate questions from shareholders who are present at the Annual Meeting.

        The fees we paid to Deloitte & Touche in 2004 are shown in the table appearing in this proxy statement under the heading "Additional Information—Auditors."

        If the shareholders do not ratify the selection of Deloitte & Touche LLP as the Company's independent public accountants, the selection of accountants will be reconsidered by the Audit Committee.

Required Vote

        The affirmative vote of holders of a majority of the votes properly cast at the Annual Meeting is required to ratify the selection of Deloitte & Touche LLP to serve as the Company's independent public accountants for the current fiscal year. For purposes of determining the number of votes cast, only those cast "For" or "Against" are included, and any abstentions or broker non-votes will not count in making that determination.

The Board recommends that you vote FOR the ratification of the selection of Deloitte & Touche LLP.



SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

        The following table sets forth certain information known to the Company with respect to beneficial ownership of Common Stock by (1) each director, (2) the Chief Executive Officer, and the other fourthree most highly compensated executive officers of the Company (theand Robert G. Miller and Peter Delle Donne, each of whom would have been one of the most highly compensated executive officers of the Company for 2004 but for the fact that he was no longer an executive officer of the Company as of the end of 2004 (collectively, the "Named Executive Officers"), (3)(4) all directors, the Chief Executive Officer and Named Executive Officersthe other three most highly compensated executive officers of the Company as a group and (4)(5) each shareholder known by us to be the beneficial owner of more than five percent of the Common Stock. Such information is presented as of March 1, 2004,2005, except as otherwise noted.

 
 Amount of Beneficial
Ownership(1)

 
Name

 Shares
 Percent Owned
 
Directors and Executive Officers     
C. Richard Reese(2) 2,340,071 2.7%
John F. Kenny, Jr.(3) 436,702 *%
Harold E. Ebbighausen(4) 45,255 *%
Robert G. Miller(5) 112,495 *%
Peter E. Delle Donne(6) 55,227 *%
Clarke H. Bailey(7) 98,049 *%
Constantin R. Boden(8) 60,448 *%
Kent P. Dauten(9) 1,530,183 1.8%
Eugene B. Doggett(10) 35,093 *%
B. Thomas Golisano(11) 1,872,654 2.2%
Arthur D. Little(12) 55,818 *%
Vincent J. Ryan (13) 7,660,530 8.9%
All directors and executive officers as a group (12 persons)(14) 12,991,152 15.0%

Five Percent Shareholders

 

 

 

 

 
Warren E. Buffett(15) 5,018,500 5.9%
Chieftain Capital Management, Inc.(16) 11,228,800 13.1%
T. Rowe Price Associates, Inc.(17) 5,840,078 6.8%
Thomas W. Smith(18) 5,334,259 6.2%
Thomas N. Tryforos(19) 4,599,586 5.4%
Scott J. Vassalluzo(20) 4,611,770 5.4%
 
 Amount of Beneficial
Ownership(1)

 
Name

 Shares
 Percent Owned
 
Directors and Executive Officers     
C. Richard Reese(2) 3,507,671 2.7%
John F. Kenny, Jr.(3) 579,527 *%
Robert T. Brennan(4)   
Harold E. Ebbighausen(5) 83,013 *%
Robert G. Miller(6) 184,038 *%
Jean A. Bua(7) 63,374 *%
Peter E. Delle Donne(8) 103,852 *%
Clarke H. Bailey(9) 149,687 *%
Constantin R. Boden(10) 93,285 *%
Kent P. Dauten(11) 2,027,128 1.6%
B. Thomas Golisano(12) 2,636,594 2.0%
Arthur D. Little(13) 39,199 *%
Vincent J. Ryan (14) 11,476,302 8.8%
All directors and executive officers as a group (11 persons)(15) 20,839,818 16.0%

Five Percent Shareholders

 

 

 

 

 
Davis Selected Advisers, L.P.(16) 15,952,422 12.3%
T. Rowe Price Associates, Inc. (17) 8,308,066 6.4%
Thomas W. Smith (18) 7,534,243 5.8%
Scott J. Vassalluzo(19) 6,637,082 5.1%
Daniel J. Englander (20) 42,975 *%

*
Less than 1%

(1)
Except as otherwise indicated, the persons named in the table above have sole voting and investment power with respect to all shares of Common Stock shown as beneficially owned by them.

(2)
Mr. Reese is a director, Chairman of the Board, Chief Executive Officer and President of the Company. Includes 41,53663,744 shares of Common Stock held in trusts for the benefit of Mr. Reese's children, as to which shares Mr. Reese disclaims beneficial ownership. Also includes 1,311,3731,967,059 shares of Common Stock as to which Mr. Reese shares beneficial ownership with Schooner Capital Trust ("Schooner Trust") as a result of a 19951988 deferred compensation arrangement, as amended, between Schooner Trust and Mr. Reese relating to Mr. Reese's former services as President of the predecessor corporation to Schooner Trust.Capital Corporation. Pursuant to such arrangement, upon the earlier to occur of (1) Schooner Trust'sthe sale or exchange by Schooner Trust of substantially all of the shares of Common Stock held by Schooner Trust or (2) the cessation of Mr. Reese's employment with the Company,