UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No.     )

  Filed by the Registrant    ☒                                   Filed by a party other than the Registrant    ☐

  Check the appropriate box:

1925 West Field Court,3100 Sanders Road, Suite 200301

Lake Forest,Northbrook, IL 6004560062

March 20, 202023, 2021

Dear Stockholders,

You are cordially invited to attend the Annual Meeting of Stockholders of IDEX Corporation (the Company), in a virtual format only via the Internet, which will be held on Thursday,Wednesday, May 7, 2020 ,12, 2021, at 9:00 a.m. Central Time, atTime. In order to attend the DoubleTree Hotel, 5460 N. River Road, Rosemont, Illinois 60018.Annual Meeting, vote during the Annual Meeting and submit questions, stockholders must go to http://www.virtualshareholdermeeting.com/IEX2021 and enter the 16-digit control number found in their proxy materials.

We intendThe meeting will be held virtually due to hold our annual meeting in person. However, we are actively monitoring the novel coronavirus disease,continuing public health impact of the COVID-19 as partpandemic and to support the health and well-being of our effort to maintain a safeIDEX management and healthy environment at our annual meeting. In the event it is not possible or advisable to hold our annual meeting in person, we will announce alternative arrangements for the meeting as promptly as practicable, which may include holding the meeting solely by means of remote communication. If we take this step, details on how to participate will be issued by press release, posted on our website, and filed with the Securities and Exchange Commission as additional proxy material. We also encourage attendees to review guidance from public health authorities on this issue.

stockholders. The following pages contain our notice of annual meeting and proxy statement. Please review this material for information concerning the business to be conducted at the 20202021 Annual Meeting, including the nominees for election as directors.of directors named in this proxy statement.

As we did last year, we have elected toWe will provide access to our proxy materials and 20192020 Annual Report on the Internet and are mailing paper copies only to those stockholders who have requested them. For further details, please refer to the section entitled Summary beginning on page 1 of the proxy statement.

Whether or not you plan to attend the 20202021 Annual Meeting, it is important that your shares be represented. Please vote via telephone, the Internet or proxy card. If you own shares through a bank, broker or other nominee, please execute your vote by following the instructions provided by such nominee.

On behalf of the Board of Directors, I would like to express our appreciation for your continued interest in the Company.

Sincerely,

ANDREW K. SILVERNAILWILLIAM M. COOK

Chairman of the Board and

Chief Executive Officer

NOTICE OF 20202021 ANNUAL MEETING OF STOCKHOLDERS

TABLE OF CONTENTS

i

PROPOSALS TO BE VOTED ON AT THE 20202021 ANNUAL MEETING

PROPOSAL 1 — ELECTION OF DIRECTORS

The Company’s Restated Certificate of Incorporation, as amended, provides for a three-class Board of Directors, with one class being elected each year for a term of three years. The Board currently consists of teneleven members, four of whom are Class I directors whose terms will expire at this year’s Annual Meeting, three of whom are Class II directors whose terms will expire at thethis year’s Annual Meeting, to be held in 2021, and three of whom are Class III directors whose terms will expire at the Annual Meeting to be held in 2022.2022, and four of whom are Class I directors whose terms will expire at the Annual Meeting to be held in 2023.

Cynthia J. Warner, a Class II director since 2013, is retiring from the Board immediately following this year’s Annual Meeting and will not stand for reelection at the Annual Meeting. Accordingly, the size of the Board will be reduced to ten members following the Annual Meeting. The Company is grateful to Ms. Warner for her invaluable insights and contributions during her Board service, including her leadership as Chair of the Nominating and Corporate Governance Committee.

Overview of IDEX Board of Directors

Our directors have a proven record of success, exhibit high integrity, are loyal to the Company and committed to its success and have knowledge of corporate governance and practices. Ten out of our 11 current directors are independent, the average tenure of our directors is 5.7 years, and the average age of our directors is 59.6 years old. The matrix below illustrates the diverse set of skills, knowledge, experiences, backgrounds and personal attributes represented on our Board.

Set forth below is a summary of the Board’s collective qualifications, experiences and backgrounds.

Senior Leadership Experience Current or Former CEO Other Public Company Board Experience Broad International Experience Extensive M&A Experience Extensive Knowledge of IDEX's Business and Industry High Level of Financial Literacy Number of Directors 0 1 2 3 4 5 6 7 8 9 10

The Board has nominated fourthree individuals for election as Class III directors to serve for a three-year term expiring at the Annual Meeting to be held in 2023,2024, or upon the election and qualification of their successors. The nominees of the Board are Andrew K. Silvernail, Katrina L. Helmkamp,William M. Cook, Mark A. BeckButhman and Carl R. Christenson,Lakecia N. Gunter, each of whom is currently serving as a director of the Company. Ms. Gunter was recommended by a third-party search firm the Nominating and Corporate Governance Committee retained at the expense of the Company.

The nominees and the other incumbent directors serving in Class II and Class III whose terms expire in future years and who will continue to serve after the Annual Meeting are listed below, with brief statements setting forth their present principal occupations and other information, including any directorships in other public companies, and their particular experiences, qualifications, attributes and skills that led to the conclusion they should serve as directors. If for any reason any of the nominees are unavailable to serve, proxies solicited hereby may be voted for a substitute. The Board, however, expects the nominees to be available.

20202021 DIRECTOR NOMINEES

Mr. SilvernailCook was appointed Chairman of the Board effective January 1, 2012. Mr. Silvernail has served as Chief Executive Officer and a director of the Company since August 10, 2011. From August 10, 2011 to February 21, 2020, Mr. Silvernail also served as President of the Company. Prior to that, Mr. Silvernail served since January 2011 as Vice President Group Executive of the Company’s Health & Science Technologies, Global Dispensing and Fire & Safety/Diversified Products business segments. From February 2010 to December 2010, Mr. Silvernail was Vice President Group Executive of the Company’s Health & Sciences Technologies and Global Dispensing business segments. Mr. Silvernail joined IDEX in January 2009 as Vice President Group Executive of Health & Science Technologies.

Andrew K. Silvernail Age: 48 Director since August 2011 Chairman, President and Chief Executive Officer

Mr. Silvernail’s relevant experience with engineering and technology industries in general, together with his extensive management experience, led to the conclusion that he should serve on the Board of Directors.

Mr. Silvernail received a bachelor of science degree in government from Dartmouth College and a master of business administration degree from Harvard University.

Mr. Silvernail is a director of Stryker Corporation.

Ms. Helmkamp has served as Chief Executive Officer of Cartus Corporation, the relocation services subsidiary of Realogy Holdings Corp., the largest full-service residential real estate services company in the United States, since June 2018. Previously, Ms. Helmkamp served as Chief Executive Officer of Lenox Corporation from November 2016 to June 2018. Prior to Lenox Corporation, Ms. Helmkamp served as Chief Executive Officer of SVP Worldwide from 2010 through 2014, and as Senior Vice President, North America Product for Whirlpool Corporation from 2008 to 2010.

Katrina L. Helmkamp Age: 53 Director since November 2015 Independent Committees: Compensation Nominating and Corporate Governance

Ms. Helmkamp’s operating leadership skills and her experience across multiple markets and technologies led to the conclusion that she should serve on the Board of Directors. During her time at SVP Worldwide and Whirlpool Corporation, Ms. Helmkamp was responsible for managing the operations and profitability of global businesses that derived a substantial portion of their revenues from outside of the United States.

Ms. Gunter has served since May 2020 as Vice President and General Manager of IoT Global and Strategic Engagement at Microsoft Corporation, a leading global developer, manufacturer and licensor of consumer electronics. From April 2018 to May 2020, Ms. Gunter was Vice President of the Programmable Solutions Group and General Manager of Ecosystem Development and Operations at Intel Corporation, a leading global designer, manufacturer and marketer of computer products and technologies. Prior to that since October 2008, Ms. Gunter served in several leadership roles at Intel, including Chief of Staff and Technical Assistant to the CEO. Prior to joining Intel, Ms. Gunter held several positions at the Department of Defense from 2004 to 2008.

Lakecia N. Gunter Age: 48 Director since January 2021 Independent Committees: Compensation

Ms. Gunter’s deep technology and digital innovation experience and her extensive strategic and commercial leadership experience gained at two Fortune 50 companies led to the conclusion that she should serve on the Board of Directors. Ms. Gunter has successfully developed and executed strategic initiatives to create new business models and to accelerate the growth and increase the profitability of multiple technology solutions. Ms. Gunter architected the operating model to transform Intel from a PC-centric company to a data-centric company, which transformation led to a greater than 50% increase in revenues within 18 months.

Ms. Gunter received a bachelor of science degree in computer engineering from the University of South Florida and a master of science degree in electrical engineering from the Georgia Institute of Technology.

OTHER INCUMBENT DIRECTORS

Class III: Three-Year Term Expires in 2022

Mr. Mrozek served as Vice Chairman and Chief Financial Officer of The ServiceMaster Company, a residential and commercial service company, until his retirement in March 2008.

Mr. Mrozek’s strategic and operating leadership skills, his extensive experience and expertise in the business services industry and his financial reporting expertise led to the conclusion that he should serve on the Board of Directors. Through over 20 years of executive experience in various senior positions in general management, operations and finance at ServiceMaster, including more than eight years as President and Chief Operating Officer of ServiceMaster or one of its largest segments, Mr. Mrozek developed extensive knowledge of the business services industry and gained valuable financial expertise and experience in mergers and acquisitions.

Ernest J. Mrozek Age: 6567 Director since July 2010 Independent Committees: Audit

Prior to joining ServiceMaster in 1987, Mr. Mrozek spent 12 years in public accounting with Arthur Andersen & Co. Mr. Mrozek has also acquired substantial experience in corporate governance as a director on the boards of several public and private companies.

Mr. Mrozek received a bachelor of science degree in accountancy with honors from the University of Illinois and is a certified public accountant, on inactive status.

Mr. Mrozek isformerly served as a director of Advanced Disposal Services, Inc. and G&K Services Inc.

Mr. Satterthwaite has served since October 2019March 2021 as President and Chief Operating OfficerVice Chairman of Cummins, Inc., a global power leader that designs, manufactures, distributes and services diesel and natural gas engines and engine-related component products. Prior to that since October 2019, he was President and Chief Operating Officer of Cummins. From April 2015 through October 2019, Mr. Satterthwaite served as President of Cummins Distribution Business, a unit of Cummins. Prior to that, Mr. Satterthwaite served as President of Cummins Power Generation from June 2008 to April 2015.

Livingston L. Satterthwaite Age: 5860 Director since April 2011 Independent Committees: Compensation (Chair) Nominating and Corporate Governance

Mr. Satterthwaite’s business leadership and sales skills, international experience and extensive experience in industrial manufacturing led to the conclusion that he should serve on the Board of Directors. Since joining Cummins in 1988, Mr. Satterthwaite has held various positions at Cummins Power Generation and other divisions of Cummins, including 14 years in managerial and sales positions in the United Kingdom and Singapore.

Prior to joining Cummins, Mr. Satterthwaite spent four years at Schlumberger Limited, an oil field services provider, as a general field engineer.

Mr. Satterthwaite received a bachelor of science degree in civil engineering from Cornell University and a master of business administration degree from Stanford University.

Mr. Parry served as Vice Chairman of Illinois Tool Works Inc. (ITW) from 2010 until his retirement in April 2017. From prior to 2009 until 2010, Mr. Parry was Executive Vice President of ITW with responsibility for the Polymers and Fluids Group.

Mr. Parry’s strategic and operating leadership skills and global commercial perspective gained from over 30 years of international business leadership experience, his significant acquisition experience and his extensive

expertise in the industrial products manufacturing industry led to the conclusion that he should serve on the Board of Directors. During 18 years of executive and management experience in various senior management positions at ITW, a multinational manufacturer of a diversified range of industrial products and equipment, Mr. Parry successfully grew the operations and profitability of multiple business units and helped ITW complete numerous acquisitions.

David C. Parry Age: 6567 Director since December 2012 Independent Committees: Compensation Nominating and Corporate Governance

Prior to joining ITW in 1994, Mr. Parry spent 17 years in various executive and management positions at Imperial Chemical Industries, which at the time was one of the largest chemical producers in the world.

Mr. Parry received a bachelor of science degree in chemistry, a master of science degree in chemistry and a Ph.D. in polymer chemistry from Victoria University of Manchester, Manchester, England.

Mr. Parry previously served as a director of Celanese Corporation.

Class I: Three-Year Term Expires in 2023

Ms. Helmkamp has served as President and Chief Executive Officer of Cartus Corporation, the relocation services subsidiary of Realogy Holdings Corp., the largest full-service residential real estate services company in the United States, since June 2018. Previously, Ms. Helmkamp served as Chief Executive Officer of Lenox Corporation from November 2016 to June 2018. Prior to Lenox Corporation, Ms. Helmkamp served as Chief Executive Officer of SVP Worldwide from 2010 through 2014, and as Senior Vice President, North America Product for Whirlpool Corporation from 2008 to 2010.

Katrina L. Helmkamp Age: 55 Director since November 2015 Independent Committees: Compensation Nominating and Corporate Governance (Chair)

Ms. Helmkamp’s operating leadership skills and her experience across multiple markets and technologies led to the conclusion that she should serve on the Board of Directors. During her time at

SVP Worldwide and Whirlpool Corporation, Ms. Helmkamp was responsible for managing the operations and profitability of global businesses that derived a substantial portion of their revenues from outside of the United States.

In addition, Ms. Helmkamp successfully oversaw numerous new product development and technology initiatives, including the launch of new products and service categories with improved margins and quality. Ms. Helmkamp also has significant mergers and acquisitions experience, both in identifying and evaluating potential targets, as well as leading post-acquisition integration activities.

Ms. Helmkamp received a bachelor of science degree in industrial engineering and a master of business administration degree from Northwestern University.

Mr. Beck is the co-founder and Chief Executive Officer of B-Square Precision, LLC, a private company engaged in the acquisition and management of companies that manufacture high-precision tools, dies, molds and components. Previously, Mr. Beck served as President and Chief Executive Officer of JELD-WEN Holding, Inc. JELD-WEN, one of the world’s largest door and window manufacturers, from November 2015 to February 2018, and was a director of JELD-WEN from May 2016 to February 2018. Prior to JELD-WEN, Mr. Beck served as an Executive Vice President at Danaher Corporation, leading Danaher’s water quality and dental programs, beginning in April 2014. Previously, he spent 18 years with Corning Incorporated in a series of management positions with increasing responsibility, culminating in his appointment as Executive Vice President overseeing Corning’s environmental technologies and life science units in July 2012. He also served on the board of directors of Dow-Corning Corporation from 2010 to 2014.

Mark A. Beck Age: 55 Director since January 2018 Independent Committees: Audit

Mr. Beck’s experience as a chief executive officer of a public company with significant international operations and his track record of innovation and successfully integrating acquired businesses led to the conclusion that he should serve on the Board of Directors.

Mr. Beck received a bachelor of arts degree in business management from Pacific University and a master of business administration degree from Harvard University.

Mr. Beck is chairman of the board of Owens & Minor, Inc.

Mr. Christenson has served since April 2014 as Chief Executive Officer and Chairman of the Board of Directors of Altra Industrial Motion Corp. Altra, a leading global designer, producer and marketer of a wide range of electromechanical power transmission motion control products. From January 2009 to April 2014, Mr. Christenson served as President and Chief Executive Officer of Altra. Prior to that, Mr. Christenson served as President and Chief Operating Officer of Altra from January 2005 to December 2008. From 2001 to 2005, Mr. Christenson was President of Kaydon Bearings, a manufacturer of custom-engineered bearings and a division of Kaydon Corporation. Prior to joining Kaydon, Mr. Christenson held several management positions at TB Wood’s Incorporated and several positions at the Torrington Company, a division of Ingersoll Rand.

Carl R. Christenson Age: 61 Director since June 2019 Independent Committees: Compensation Nominating and Corporate Governance

Mr. Christenson’s extensive experience leading industrial businesses and executing strategic acquisitions, including in his current role as chief executive officer of a public company with global operations, led to the conclusion that he should serve on the Board of Directors.

Mr. Christenson received bachelor of science and master of science degrees in Mechanical Engineering from the University of Massachusetts and a master of business administration degree from Rensselaer Polytechnic Institute.

Mr. Ashleman was appointed a director and Chief Executive Officer of the Company in December 2020. He has served as President of the Company since February 2020. Prior to that, Mr. Ashleman served since July 2015 as the Company’s Chief Operating Officer. From February 2014 to July 2015, Mr. Ashleman was Senior Vice President and Group Executive of the Company’s Global Dispensing, Fire & Safety/Diversified Products and Health & Science and Optics business segments. From September 2011 to February 2014, Mr. Ashleman was Vice President and Group Executive of the Company’s Fire & Safety/Diversified Products business segment. From April 2010 to September 2011, Mr. Ashleman was President of Gast Manufacturing and Global Dispensing. Mr. Ashleman joined IDEX in March 2008 as President of Gast Manufacturing.

Eric D. Ashleman Age: 54 Director since December 2020 Chief Executive Officer and President

Mr. Ashleman’s significant industrial manufacturing and operations experience, coupled with his extensive management experience, led to the conclusion that he should serve on the Board of Directors. Mr. Ashleman has been integral to the Company’s success, including his role in developing our distinct culture, business model and global strategy.

Mr. Ashleman received a bachelor of arts degree in economics and a master of business administration degree from the University of Michigan.

Mr. Ashleman is a director of Modine Manufacturing Co.

NOT STANDING FOR REELECTION

Ms. Warner has served as President and Chief Executive Officer and as a director of Renewable Energy Group, Inc., an advanced biofuel producer, since January 2019. Previously, Ms. Warner served as Executive Vice President, Operations for Andeavor (formerly known as Tesoro Corporation) from August 2016 until October 2018, when Andeavor was acquired by Marathon Petroleum Corp. Prior to that, Ms. Warner served as Andeavor’s Executive Vice President, Strategy and Business Development, since October 2014. From 2012 to 2014, Ms. Warner was Chairman and Chief Executive Officer of Sapphire Energy, Inc. From 2009 to 2011, Ms. Warner was Chairman and President of Sapphire Energy. Prior to 2009, Ms. Warner was Group Vice President, Global Refining, at BP plc.

Cynthia J. Warner Age: 62 Director since February 2013 Independent Committees: Compensation Nominating and Corporate Governance

Ms. Warner’s operating leadership skills, international experience and extensive experience in the energy, refining and transportation industries led to the conclusion that she should serve on the Board of Directors. During her 25 years at BP and Amoco, Inc. (prior to its acquisition by BP), Ms. Warner gained significant knowledge of the global energy industry and served in numerous leadership roles, including overseeing BP’s Global Refining business and its health, safety, security and environmental efforts, with a consistent record of success in coordinating the operations of thousands of employees across BP’s global facilities.

In her role as Chief Executive Officer of Sapphire Energy, an alternative energy venture, Ms. Warner had oversight responsibility for the raising of substantial investment capital and the successful completion of a new demonstration facility for the company.

Ms. Warner received a bachelor of engineering degree in chemical engineering from Vanderbilt University and a master of business administration degree from Illinois Institute of Technology.

Ms. Warner is a director of Sempra Energy.

COMPENSATION OF DIRECTORS

The objectives of our director compensation program are to attract highly-qualified individuals to serve on our Board and to align our directors’ interests with the interests of our stockholders. The Compensation Committee periodically reviews the program to ensure that it continues to meet these objectives.

The Company believes that to attract and retain qualified directors, pay levels should be targeted at the 50th percentile (or median) of pay levels for directors at comparable companies. On at least a biennial basis, the Compensation Committee, with the assistance of F.W. Cook, evaluates the competitiveness of director compensation. The primary reference point for the determination ofto determine market pay is the peer group of companies. The peer group used in this analysis was the same peer group used for the Company’s executive compensation analysis.

For further details on this topic, refer to “Peer Companies” under “Setting Executive Compensation” in the Compensation Discussion and Analysis below. Market composite data derived from pay surveys available to F.W. Cook and to the Company is also used.

Our director compensation for 2019 and 2020 is set forth below. The changes forIn December 2020, are detailed in the Company’s Amended and RestatedMr. Cook was appointed Non-EmployeeNon-Executive Director Compensation Policy (Director Compensation Policy) and reflect market-based adjustments as a resultChairman of the analysis described above.Board and his additional fee is listed below.

20192020 Director Compensation

The following table summarizes the total compensation earned in 20192020 for the Company’snon-management directors. Neither Mr. Ashleman nor Mr. Silvernail receives noreceived any additional compensation for his service as a director.director during 2020.

Directors’ Outstanding Equity Awards at 20192020 Fiscal Year End

The following table provides information on restricted stock units and stock option awards held by the Company’snon-management directors and the value of those awards as of December 31, 2019.2020. All outstanding awards are in or exercisable for shares of Common Stock.

SECURITY OWNERSHIP

The following table furnishes information as of March 13, 2020,15, 2021, except as otherwise noted, with respect to shares of Common Stock beneficially owned by (i) each director and nominee for director, (ii) each executive officer named in the Summary Compensation Table, (iii) directors, nominees and executive officers of the Company as a group, and (iv) any person who is known by the Company to be a beneficial owner of more than five percent of the outstanding shares of Common Stock.

Except as indicated by the notes to the following table, the holders listed below have sole voting power and investment power over the shares beneficially held by them. Under SEC rules, the number of shares shown as beneficially owned includes shares of Common Stock subject to options that are exercisable currently or will be exercisable within 60 days of March 13, 2020.15, 2021. Shares of Common Stock subject to options that are exercisable within 60 days of March 13, 2020,15, 2021, are considered to be outstanding for the purpose of determining the percentage of shares held by a holder, but not for the purpose of computing the percentage held by others. An * indicates ownership of less than one percent of the outstanding Common Stock.

For purposes of the following table, the address for each of the directors, nominees for director and executive officers of the Company is c/o 1925 West Field Court,3100 Sanders Road, Suite 200, Lake Forest, Illinois 60045.301, Northbrook, IL 60062.