Our commitment to good corporate governance stems from our belief that a strong governance framework creates long-term value for our shareholders, strengthens Board and management accountability, and builds trust in us and our brand. Our governance framework includes the following highlights:

There are fourthree matters scheduled for a vote:

Shareholders of record at the close of business on August 21, 201819, 2019 are entitled to attend and vote at the meeting. Each share of our common stock is entitled to one vote on all matters to be voted on at the meeting, and can be voted only if the record owner is present to vote or is represented by proxy. The proxy card provided with this proxy statement indicates the number of shares of common stock that you own and are entitled to vote at the meeting.

All holders of Mercury shares as of the record date are encouraged to attend the annual meeting. In order to ensure the safety of all attendees, we have implemented the following security and admission policies.

The presence at the meeting, in person or represented by proxy, of the holders of a majority of our common stock outstanding on August 21, 2018,19, 2019, the record date, will constitute a quorum for purposes of the meeting. On the record date, 48,412,44555,466,500 shares of our common stock were outstanding. For purposes of determining whether a quorum exists, proxies received but marked “abstain” and so-called “broker non-votes” (described below) will be counted as present.

A broker holding your shares in “street name” must vote those shares according to any specific instructions it receives from you. If specific instructions are not received, your broker may vote your shares in its discretion, depending on the type of proposal involved. Under applicable rules, there are certain matters on which brokers may not vote without specific instructions from you, such as the election of directors and the advisory vote on say-on-pay, and the vote on approval of our 2018 Stock Incentive Plan.say-on-pay. If such matters come before the meeting and you have not specifically instructed your broker how to vote your shares, your shares will not be voted on those matters, giving rise to what is called a “broker non-vote.” Shares represented by broker non-votes will be counted for purposes of determining the existence of a quorum for the transaction of business, but for purposes of determining the number of shares voting on a particular proposal, broker non-votes will not be counted as votes cast or shares voting.

We bear the cost of preparing, assembling, and mailing the proxy material relating to the solicitation of proxies by the Board of Directors for the meeting. In addition to the use of the mails, certain of our officers and regular employees may, without additional compensation, solicit proxies in person, by telephone, or by other means of communication. We will also request brokerage houses, custodians, nominees, and fiduciaries to forward copies of the proxy material to those persons for whom they hold shares, and will reimburse those record holders for their reasonable expenses in transmitting this material.

Our by-laws provide for a Board of Directors of not fewer than three nor more than fifteen directors. As permitted by Massachusetts law, the Board of Directors is divided into three classes, with each class consisting, as nearly as may be possible, of one-third of the whole number of the Board of Directors. The Board of Directors currently consists of nineeight members, with James K. Bass, Michael A. Daniels, and Lisa S. Disbrow serving as Class I directors, Mark Aslett, Mary Louise Krakauer, and William K. O’Brien serving as Class II directors, and George K. Muellner, Mark S. Newman,Barry R. Nearhos and Vincent Vitto serving as Class III directors.

The Board of Directors believes that the Board, as a whole, should possess a combination of skills, professional experience, and backgrounds necessary to oversee the Company’s business. In addition, the Board of Directors believes that there are certain attributes that every director should possess, as reflected in the Board’s membership criteria. Accordingly, the Board of Directors and the Nominating and Governance Committee consider the qualifications of directors and director candidates individually and in the broader context of the Board of Directors’ overall composition and the Company’s current and future needs.

The persons named as proxies in the accompanying proxy card will vote, unless authority is withheld, for the election of the twothree Class I nominees and the one Class III nomineesnominee named below. We have no reason to believe that any of the nominees will be unavailable for election. However, if any one of them becomes unavailable, the persons named as proxies in the accompanying proxy card have discretionary authority to vote for a substitute chosen by the Board. Any vacancies not filled at the meeting may be filled by the Board.

The Board of Directors has determined that a majority of the members of the Board should consist of “independent directors,” determined in accordance with the applicable listing standards of the NASDAQ Global Select Market as in effect from time to time. Directors who are also Mercury employees are not considered to be independent for this purpose. For a non-employee director to be considered independent, he or she must not have any direct or indirect material relationship with Mercury. A material relationship is one which, in the opinion of the Board, would interfere with the exercise of independent judgment in carrying out the responsibilities of a director. In determining whether a material relationship exists, the Board considers, among other things, the circumstances of any direct compensation received by a director or a member of a director’s immediate family from Mercury, any professional relationship between a director or a member of a director’s immediate family and Mercury’s outside auditors, any participation by a Mercury executive officer in the compensation decisions of other companies employing a director or a member of a director’s immediate family as an executive officer, and commercial relationships between Mercury and other entities with which a director is affiliated (as an executive officer, partner, or controlling shareholder). The Board has determined that directors who serve on the Audit Committee must qualify as independent under the applicable rules of the Securities and Exchange Commission (“SEC”), which limit the types of compensation an Audit Committee member may receive directly or indirectly from Mercury and require that Audit Committee members not be “affiliated persons” of Mercury or its subsidiaries. In addition, the Board of Directors has determined that directors who serve on the Compensation Committee must satisfy the standards for being considered a “non-employee director” within the meaning of Securities and Exchange Commission Rule 16b-3 and an “outside director” for purposes of Section 162(m) of the Internal Revenue Code.

Our Nominating and Governance Committee is responsible for identifying and recommending nominees for election to the Board. The Committee will consider nominees recommended by a shareholder if the shareholder submits the nomination in compliance with applicable requirements. The Committee did not receive any shareholder nominations for election of directors at this year’s meeting. With respect to the nominees for Class I director standing for election at the meeting, Messrs. Bass and Daniels were each most recently elected as a Class I director at the 2016 Annual Meeting of Shareholders and Ms. Disbrow was most recently elected as a Class I director at the 2017 Annual Meeting of Shareholders. With respect to the

Yes. Shareholders who wish to communicate with the Board or with a particular director may send a letter to Mercury Systems, Inc., 50 Minuteman Road, Andover, Massachusetts 01810, attention: Secretary. The mailing envelope should contain a clear notation that the enclosed letter is a “Shareholder-Board Communication” or “Shareholder-Director Communication.” All such letters should clearly state whether the intended recipients are all members of the Board or certain specified individual directors. Our Secretary will make copies of all such letters and circulate them to the appropriate director or directors.

The Audit Committee assists the Board in its oversight of management’s conduct of our accounting and financial reporting processes, including by providing oversight with respect to the financial reports and other financial information provided by our systems of internal accounting and financial controls, and the annual audit of our financial statements. The Audit Committee also reviews the qualifications, independence, and performance of our independent registered public accounting firm, pre-approves all audit and non-audit services provided by such firm and its fees, and discusses with management and our independent registered public accounting firm the quality and adequacy of our internal control over financial reporting. The Audit Committee is directly responsible for the appointment, compensation, retention, and oversight of the work of our independent registered public accounting firm, which reports directly to the Audit Committee. The Audit Committee also is responsible for reviewing and approving related-person transactions in accordance with our Code of Business Conduct and Ethics and the Audit Committee charter.

The Compensation Committee is responsible for:

The Nominating and Governance Committee assists the Board in identifying individuals qualified to become Board members, and recommends to the Board persons to be nominated for election as directors by the shareholders at the annual meeting of shareholders or by the Board to fill vacancies. The Committee has recommended the nominees for election at the annual meeting. In addition, the Committee oversees the process by which the Board and Committees each assesses its effectiveness as well as the individual director peer assessment process. The Committee also reviews our Board of Directors Policy and the charters for each of the Committees of the Board of Directors.

The M&A and Finance Committee was created in 2017 to formalize our prior ad hoc M&A Review Committee, to assistassists the Board in reviewing and assessing M&A transactions. The Committee is comprised of at least three members, all independent directors, as appointed by the Board. The Board has delegated to the Committee the authority to approve the acquisition or disposition of any other company, or any division, business unit or line of business of Mercury, for a purchase price of up to $25 million. The Committee also serves as the pricing committee for any of the Company's capital markets activities.

The Board of Directors met sevennine times during fiscal 2018.2019. The table below reports information about the committees during fiscal 2018:

Directors are encouraged to attend the annual meeting of shareholders, or special meeting in lieu thereof; however, we do not have a formal policy with respect to attendance at shareholder meetings. All of the directors then in office attended the 20172018 annual meeting of shareholders.

The CEO is expected to own or control, directly or indirectly, shares of Mercury common stock with a value of at least five times the CEO’s base salary. The CEO is expected to meet this guideline within five years of first becoming CEO, or within five years of April 22, 2014, whichever is later, and is expected to retain such investment in the Company as long as he or she is the CEO. Prior to meeting the five times holding requirement per this guideline, after applicable tax withholding on the vesting of an equity award, the CEO is required to retain 50% of the net, after tax award until he or she is in compliance with the stock ownership guideline. Exceptions to this stock ownership guideline may be approved from time to time by the Board as it deems necessary to address individual circumstances. Mr. Aslett's holdings of our common stock satisfy the stock ownership guidelines.

Yes. Our Code of Business Conduct and Ethics includes a means for the anonymous reporting of any concerns about accounting, internal accounting controls, or auditing matters. Any employee, supplier, customer, shareholder, or other interested party can submit a report via the following anonymous methods:

Yes. We have adopted a written policy which provides for the review and approval by the Audit Committee of transactions involving Mercury in which a related person is known to have a direct or indirect interest and that are required to be reported under Item 404(a) of Regulation S-K promulgated by the SEC. For purposes of this policy, a related person includes: (1) any of our directors, director nominees, or executive officers; (2) any known beneficial owner of more than 5% of any class of our voting securities; or (3) any immediate family member of any of the foregoing. In situations where it is impractical to wait until the next regularly scheduled meeting of the Audit Committee or to convene a special meeting of the Committee, the Chair of the Committee has been delegated authority to review and approve related-person transactions. Transactions subject to this policy may be pursued only if the Audit Committee (or the Chair of the Committee acting pursuant to delegated authority) determines in good faith that, based on all the facts and circumstances available, the transactions are in, or are not inconsistent with, the best interests of Mercury and our shareholders.

No, Mercury does not have a shareholder rights agreement or other "poison pill".

Our Chief Executive Officer and senior management are principally responsible for risk identification, management, and mitigation. Our senior management engages in an enterprise risk management (“ERM”) process each fiscal year. The process consists of an annual assessment of risks and an ongoing review of risk mitigation efforts and assessment of new risk developments. At regularly scheduled Board meetings, our Senior Director of Internal Audit reviews the key risks identified in the ERM process and management’s plans for mitigating such risks. Our directors have the opportunity to evaluate such risks and mitigation plans, to ask questions of management regarding those risks and plans, and to offer their ideas and insights to management as to these and other perceived risks and the implementation of risk mitigation plans.

Our Board Policy provides that the Chairman of the Board will be elected from among the independent directors, barring the Board’s specific determination otherwise. If, in its judgment the Board determines that election of a non-independent Chairman would best serve the Company at a particular time, such a Chairman would be excluded from executive sessions of the independent directors. In such case, a Lead Independent Director, as appointed from time to time, would preside over executive sessions and would perform such other duties as might be determined from time to time by the Board.

Our general employee compensation programs are substantially less weighted toward incentive compensation and equity awards than those for our executive officers. While managers below the executive officers do have incentive

Directors who are also our employees receive no additional compensation for serving on the Board of Directors. During fiscal 2018,2019, our non-employee directors received an annual cash retainer of $55,000 and the following positions received additional cash retainers:

New non-employee directors are granted restricted stock awards in connection with their first election to the Board. These awards are granted by the Board of Directors and consist of shares of restricted stock for the number of shares of common stock equal to $225,000 divided by the average closing price of our common stock during the 30 calendar days prior to the date of grant. These awards vest as to 50% of the covered shares on each of the first two anniversaries of the date of grant.

The Compensation Committee, with the assistance of the Committee's independent compensation consultant, performed its annual review of the Company's compensation for non-employee directors. Based on market data, including data for our peer group, the Compensation Committee recommended, and the Board of Directors approved, the following changes to the compensation policy for non-employee directors effective for fiscal 2019:2020:

This vote is advisory, which means that the vote on executive compensation is not binding on us, our Board of Directors, or the Compensation Committee. The vote on this resolution is not intended to address any specific element of compensation, but rather relates to the overall compensation of our named executive officers, as described in this proxy statement in accordance with the compensation disclosure rules of the Securities and Exchange Commission. To the extent there is a significant vote against our named executive officer compensation as disclosed in this proxy statement, the Compensation Committee will evaluate whether any actions are necessary to address our shareholders’ concerns.

Approval of the ratification of the appointment of KPMG as our independent registered public accounting firm for fiscal 20192020 requires the affirmative “FOR” vote of a majority of the votes cast on the proposal. Unless marked to the contrary, proxies received will be voted “FOR” approval of the ratification of the appointment.

The following persons are our executive officers:

The Compensation Committee has responsibility for our executive compensation philosophy and the overall design of our executive compensation programs. The Compensation Committee is primarily responsible for setting executive compensation, which in the case of our CEO, is subject to ratification by a majority of the independent directors on the Board. Information about the Compensation Committee, including its composition, responsibilities, and processes, can be found earlier in this proxy statement under “Corporate Governance—What committees has the Board established? – Compensation Committee.”

Our total compensation program consists of fixed elements, such as base salary and benefits, and variable performance-based elements, such as annual and long-term incentives. Our fixed compensation elements are designed to provide a stable source of income and financial security to our executives. For fiscal 2018,2019, our variable performance-based elements were designed to reward corporate financial performance compared to business goals for cash bonuses and growth and profitability relative to our peer group for annual performance-based equity awards.

When the Compensation Committee annually considers executive base salaries, it takes into account each executive’s role and level of responsibility. Individual compensation pay levels may vary relative to the market based on individual performance and other considerations, including the initial compensation levels required to attract qualified new hires and the compensation levels required to retain highly qualified executives.

In establishing the executive bonus program for fiscal 2018,2019, the Compensation Committee reviewed our multi-year performance and noted that our annual financial goals have been very aggressive relative to the financial performance of our peer group, with achievement of our strategic operating plan consistently positioning us in the top quartile. In order to provide incentives for continued top quartile performance going forward, the Committee increased the potential cash bonus payout for fiscal 2018, thereby putting an even larger percentage of an executive's overall potential compensation at risk based on performance. For fiscal 2018,set the target bonus as a percentage of base salary for the Chief Executive Officer under the executive bonus program wasat 150%; for the Executive Vice President, Chief Operating Officer wasat 110%; and for each of the Executive Vice President, General Counsel and the Executive Vice President, Chief Financial Officer wasat 90%.

In fiscal 2018, the Compensation Committee targeted total direct compensation (i.e., base salary plus cash bonus opportunity plus long-term equity incentive opportunity) around the median of a composite index of data from our peer group and the Radford Global Technology Survey with targeted total cash compensation (i.e., base salary plus cash bonus opportunity) aligned to aggressive performance goals relative to such composite index. Our executive bonus program is a variable performance-based element of our overall compensation program. This bonus program provides the potential for cash compensation for our executive officers based on achieving the corporate financial performance goals contained in the annual strategic operating plan that is approved by our Board of Directors in the first month of the fiscal year. Participants in the program are senior executives who have a strategic function and are recommended by the CEO to the Compensation Committee for participation in the program. In general, executives with the highest level and amount of responsibility have the highest percentage of their total target compensation at risk. This program consists of two elements: (1) target bonuses; and (2) potential over-achievement awards. Each executive officer’s target bonus is determined based on position, responsibilities, and total target cash compensation, and may be subject to change from year to year. For fiscal 2018,2019, each executive officer’s target bonus was determined based on actual adjusted EBITDA (defined below) achieving budgeted adjusted EBITDA as set in our strategic operating plan for the fiscal year. Each executive officer's potential over-achievement award was determined based on actual adjusted EBITDA exceeding budgeted adjusted EBITDA for the fiscal year.

Adjusted EBITDA is a non-GAAP measure and all references to actual adjusted EBITDA in this Compensation Discussion and Analysis refer to such non-GAAP measure. As used in our fiscal 20182019 executive bonus plan, adjusted EBITDA includes net income from continuing operations, prior to acquisitions occurring in the plan measurement period (prior to the impact, if any, of a payout of any potential over-achievement award) and is adjusted for the following: interest income and expense; other non-operating income (expense) not otherwise adjusted for; income taxes; depreciation; amortization of acquired intangible assets; restructuring and other charges; impairment of long-lived assets; acquisition and financing costs; fair value adjustments from purchase accounting; litigation and settlement expensesexpenses; and stock-based and other non-cash compensation expense. All references to revenue are to revenue as calculated in accordance with GAAP.

A reconciliation between adjusted EBITDA and the most directly comparable GAAP financial measure is included as Appendix BA to this proxy statement.

As part of our fiscal 20182019 strategic operating plan, the Compensation Committee set the financial portion of our executive bonus plan for the first half of fiscal 20182019 at the July 20172018 meeting of the Board of Directors. The Compensation Committee set the financial portion of our executive bonus plan for the second half and full year for fiscal 20182019 at the January 20182019 meeting of the Board of Directors as part of our mid-year strategic operating plan review. Payouts for corporate financial performance for fiscal 20182019 were based on objectives for the fiscal year broken into the first half of the year and the full fiscal year, with a catch-up feature for unearned first half cash incentives based on our full year performance, and were subject to the following payout formulas:

For fiscal 2019,2020, the target bonus as a percentage of base salary for the Chief Executive Officer under the executive bonus program will be 150%; for each of the Executive Vice President, Chief Operating Officer and the Chief Financial Officer will be 110%; and for each of the Executive Vice President, Chief Financial Officer and the Executive Vice President, General Counsel will be 90%. For fiscal 2019,2020, the performance targets are based on our growth goals and margin expansion plans that are translated into a target level of adjusted EBITDA measured in dollars compared to budgeted adjusted EBITDA as set forth in our strategic operating plan for fiscal 2019,2020, with targets again relating to the first and second halves of the fiscal year.

We believe that compensation in the form of Mercury stock should be a significant portion of our executive officers’ total compensation in order to align with shareholder interests. Equity compensation creates a link to the creation of shareholder value. Our 2005 Stock Incentive Plan allows for several types of equity instruments, including stock options, stock appreciation rights, restricted stock, and deferred stock awards. Our 2018 Stock Incentive Plan, which will replacereplaced our 2005 plan for all awards granted after our 2018 annual meeting of shareholders, utilizes these same types of equity instruments. The Compensation Committee determines which instruments to use on a grant-by-grant basis. When approving equity awards for an executive officer, the Compensation Committee considers the executive’s current contribution to Mercury, the anticipated contribution to meeting our long-term strategic performance goals, and industry practices and norms. Long-term incentives granted in prior years, existing levels of stock ownership by executive officers, and aggregate grants to all executive officers are also taken into consideration. The Compensation Committee also considers the other elements of incentive compensation available to the executive officers and the performance metrics associated with those incentives, with a view toward providing an appropriately diverse set of different performance criteria and objectives to incent different aspects and time periods of performance and avoid multiple forms of reward for the same achievement.