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

SCHEDULE 14A INFORMATION

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  o

Check the appropriate box:

ALLISON TRANSMISSION HOLDINGS, INC.
(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Dear Fellow Stockholder:

It is my pleasure, along with our Board of Directors, or Board, to invite you to the 2019 annual meeting of stockholders, or the Annual Meeting, of Allison Transmission Holdings, Inc. This year’s meeting will be held on Wednesday, May 8, 2019 at 1:00 p.m. Eastern Time, at the Hyatt Regency Indianapolis, One South Capitol Avenue, Indianapolis, Indiana 46204.

You will find information regarding the business to be conducted at the Annual Meeting in the attached Notice of 2019 Annual Meeting of Stockholders and Proxy Statement, including information you should consider when you vote your shares. We are sending our stockholders a notice regarding the availability of this proxy statement, our 2018 Annual Report to Stockholders and other proxy materials via the Internet. This electronic process gives you fast, convenient access to the materials, reduces the impact on the environment and reduces our printing and mailing costs. A paper copy of these materials can be requested using one of the methods described in the materials.

Whether or not you plan to attend the Annual Meeting, your vote is important and we encourage you to vote promptly. You may vote your shares by telephone, via the Internet or, if you received a paper copy of the proxy materials, by signing, dating and returning your proxy card or voting instruction form.

Our Board unanimously recommends that you vote:

Last year was a record year for Allison. In 2018, we generated the highest Net Sales, Net Income and Adjusted EBITDA in company history, increased sales in each of our end markets and made proactive investments in our business. The Allison team accomplished this in a year of rapidly changing and challenging market conditions through hard work, focus on operational excellence and execution of our strategic imperatives. Our established and well-defined approach to capital structure and allocation remains intact. We leveraged opportunistic refinancing activities and returned capital to stockholders through quarterly dividends and $609 million of common stock repurchases. I appreciate your continued interest in and support of our company and look forward to seeing you at the Annual Meeting.

Sincerely,

David S. Graziosi
President and Chief Executive Officer

Wednesday, May 8, 2019

1:00 p.m. Eastern Time

Hyatt Regency Indianapolis, One South Capitol Avenue, Indianapolis, IN 46204

Record Date

March 11, 2019

Items of Business

Admission

In order to be admitted to the Annual Meeting, you must present (i) proof of ownership of Allison stock on March 11, 2019, which is the record date for the Annual Meeting, and (ii) a form of photo identification such as a driver’s license. Proof of ownership can be:

Voting

Your Vote is Important. Please vote your shares at your earliest convenience. This will ensure the presence of a quorum at the Annual Meeting. Promptly voting your shares via the Internet, by telephone, or, if you received a paper copy of the proxy materials, by signing, dating, and returning the accompanying proxy card or voting instruction form will save the expense and extra work of additional solicitation. Submitting your proxy now will not prevent you from voting your shares at the Annual Meeting, as your proxy is revocable at your option.

Our Board unanimously recommends that you vote:

On or about Friday, March 29, 2019, we will mail to our stockholders either (1) a copy of this proxy statement, a proxy card and our 2018 Annual Report to Stockholders or (2) a Notice Regarding the Availability of Proxy Materials, which will indicate how to access our proxy materials and vote via the Internet.

The Notice Regarding the Availability of Proxy Materials, proxy statement, form of proxy card and our 2018 Annual Report to Stockholders are available at www.proxyvote.com.

The accompanying proxy statement provides a detailed description of the business to be conducted at the Annual Meeting. We urge you to read the accompanying proxy statement carefully and in its entirety.

By order of the Board of Directors

Eric C. Scroggins
Vice President, General Counsel and Secretary

Allison Transmission Holdings, Inc.
One Allison Way
Indianapolis, Indiana 46222

This proxy statement is being provided to stockholders on or about March 29, 2019 in connection with the solicitation by the Board of Directors, or Board, of Allison Transmission Holdings, Inc., referred to in this proxy statement as Allison, we, us, our or the Company, of proxies to be voted at the 2019 annual meeting of stockholders, or the Annual Meeting, and at any adjournments or postponements thereof, for the purposes set forth in the accompanying Notice of 2019 Annual Meeting of Stockholders. The Annual Meeting will be held at 1:00 p.m. Eastern Time on Wednesday, May 8, 2019 at the Hyatt Regency Indianapolis, One South Capitol Avenue, Indianapolis, Indiana 46204.

Why did I receive a Notice of Internet Availability of Proxy Materials?

You are receiving this proxy statement because you owned shares of Allison common stock at the close of business on March 11, 2019, which is the record date for the Annual Meeting, or the Record Date, and that entitles you to vote at the Annual Meeting. By use of a proxy, you can ensure your shares are voted whether or not you attend the Annual Meeting.

We are furnishing proxy materials to our stockholders primarily via the Internet, instead of mailing printed copies of those materials to each stockholder. On or about March 29, 2019, we mailed a Notice of Internet Availability of Proxy Materials, or Notice, to certain of our stockholders. The Notice contains instructions about how to access our proxy materials and vote via the Internet. If you received a Notice and would like to receive a paper copy of our proxy materials, please follow the instructions included in the Notice. If you previously chose to receive our proxy materials electronically, you will continue to receive access to these materials via email unless you elect otherwise.

Who is entitled to vote at the Annual Meeting?

Holders of our common stock outstanding at the close of business on the Record Date are entitled to vote their shares at the Annual Meeting. As of the Record Date, 125,255,892 shares of our common stock were issued and outstanding. Each share of our common stock is entitled to one vote on each matter properly brought before the Annual Meeting.

The presence at the Annual Meeting in person or by proxy of the holders of record of a majority in voting power of the shares entitled to vote at the meeting, or 62,627,947 shares, will constitute a quorum for the transaction of business at the Annual Meeting.

What will I be voting on at the Annual Meeting and how does our Board recommend that I vote?

There are four proposals that stockholders will vote on at the Annual Meeting:

Our Board recommends that you vote:

G. Frederick Bohley, David S. Graziosi and Eric C. Scroggins, three of our executive officers, have been selected by our Board to serve as proxy holders for the Annual Meeting. All shares of our common stock represented by properly delivered proxies received in time for the Annual Meeting will be voted at the Annual Meeting by the proxy holders in the manner specified by the stockholder. If you sign and return a proxy card without indicating how you want your shares to be voted, the persons named as proxies will vote your shares in accordance with the recommendations of our Board.

What does it mean if I receive more than one Notice, proxy card or voting instruction form?

If you received more than one Notice, proxy card or voting instruction form, your shares are registered in more than one name or are registered in different accounts. Please follow the voting instructions included on each Notice, proxy card and voting instruction form to ensure that all of your shares are voted.

What is the difference between holding shares as a stockholder of record and as a beneficial owner?

If your shares are registered directly in your name with our transfer agent, American Stock Transfer & Trust Company LLC, you are considered, with respect to those shares, the “stockholder of record.” The Notice has been or will be sent directly to you, unless you previously requested printed copies of our proxy materials.

If your shares are held in a stock brokerage account or by a bank or other holder of record, you are considered the “beneficial owner” of those shares held in street name. The Notice has been or will be sent to you by your broker, bank or other holder of record who is considered, with respect to those shares, to be the stockholder of record, unless you previously requested printed copies of our proxy materials. As the beneficial owner, you have the right to direct your broker, bank or other holder of record on how to vote the shares in your account.

How do I vote?

Stockholder of Record. If you are a stockholder of record, you may vote by using any of the following methods:

Beneficial Owners. If you are a beneficial owner of shares held in street name, you may vote by using any of the following methods:

May I change my vote after I have submitted a proxy?

If you are a stockholder of record, you have the power to revoke your proxy at any time by:

If you are a beneficial owner of shares, you may submit new voting instructions by contacting your broker, bank or other holder of record. You may also revoke your previous voting instructions by voting in person at the Annual Meeting if you obtain a legal proxy from your broker, bank or other holder of record and present it at the Annual Meeting.

Is my vote confidential?

We maintain the confidentiality of the votes of individual stockholders. Ballots, proxy forms and voting instructions returned to brokerage firms, banks and other holders of record are kept confidential. Only the proxy tabulator and the inspector of election have access to the ballots, proxy forms and voting instructions. The proxy tabulator will disclose information taken from the ballots, proxy forms and voting instructions only if there is a proxy contest, if the stockholder authorizes disclosure, to defend legal claims or as otherwise required by law. If you write comments on your proxy card or ballot, management may learn how you voted in reviewing your comments.

Who will serve as the proxy tabulator and inspector of election?

A representative from Broadridge Financial Services, Inc. will serve as the independent inspector of election and will tabulate votes cast by proxy or in person at the Annual Meeting. We will report the results in a current report on Form 8-K filed with the Securities and Exchange Commission, or SEC.

What vote is required to approve each proposal?

The shares of a stockholder whose ballot is marked as “abstain” on any or all proposals will be included in the number of shares present at the Annual Meeting to determine whether a quorum is present.

If you are a beneficial owner of shares and do not provide the record holder of your shares with specific voting instructions, your record holder may vote on the ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for 2019 (Proposal No. 2). However, your record holder cannot vote your shares without specific instructions on the election of directors (Proposal No. 1), the advisory, non-binding vote to approve the compensation paid to our named executive officers (Proposal No. 3) and the advisory, non-binding vote on the frequency of future advisory votes on the compensation paid to our named

executive officers (Proposal No. 4). If your record holder does not receive instructions from you on how to vote your shares on Proposal No. 1, Proposal No. 3 or Proposal No. 4, your record holder will inform the inspector of election that it does not have the authority to vote on that proposal with respect to your shares. This is generally referred to as a “broker non-vote.” Broker non-votes will be included in the number of shares present at the Annual Meeting to determine whether a quorum is present, but they will not be counted in determining the outcome of the vote on Proposal No. 1, Proposal No. 3 or Proposal No. 4.

A proxy that is signed and returned to us will be voted in the manner directed therein. If properly signed and returned, but no such direction is made, any proxy will be voted (i) “FOR” our Board’s eleven nominees for director, (ii) “FOR” the ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for 2019, (iii) “FOR” the approval of, in an advisory, non-binding vote, the compensation paid to our named executive officers, (iv) for the option of every “1 YEAR” as the frequency of future advisory votes on the compensation paid to our named executive officers and (v) in the discretion of the proxies on such other business as may properly come before the meeting or any adjournments or postponements thereof.

The following table summarizes the votes required for passage of each proposal and the effect of abstentions and broker non-votes.

Who is paying for the cost of this proxy solicitation?

Our Board is soliciting the proxy accompanying this proxy statement. We will pay all proxy solicitation costs. Proxies may be solicited by our officers, directors and employees, none of whom will receive any additional compensation for their services. These solicitations may be made personally or by mail, facsimile, telephone, messenger, email or the Internet. We will pay persons holding shares of common stock in their names or in the names of nominees, but not owning such shares beneficially, such as brokers, banks and other holders of record, for the expense of forwarding solicitation materials to the beneficial owners.

What do I need to do to attend the meeting in person?

In order to be admitted to the Annual Meeting, you must present proof of ownership of Allison common stock on the Record Date. This can be:

Any holder of a proxy from a stockholder must present the proxy card, properly executed, and a copy of the proof of ownership. Stockholders and proxy holders must also present a form of photo identification such as a driver’s license. The Company reserves the right to deny admittance to anyone who cannot adequately show proof of stock ownership as of the Record Date or refuses to comply with our security procedures. No cameras, recording equipment, large bags, briefcases or packages will be permitted into the Annual Meeting.

Is there a list of stockholders entitled to vote at the Annual Meeting?

A list of stockholders entitled to vote at the Annual Meeting will be available at the meeting and for ten days prior to the meeting, between the hours of 8:00 a.m. and 4:00 p.m. Eastern Time, at our offices at One Allison Way, Indianapolis, Indiana 46222. If you would like to view the stockholder list, please contact our General Counsel and Secretary to schedule an appointment.

I share an address with another stockholder, and we received only one paper copy of the proxy materials. How may I obtain an additional copy of the proxy materials?

To reduce costs and reduce the environmental impact of our Annual Meeting, a single Notice or a single proxy statement and 2018 Annual Report to Stockholders, along with individual proxy cards, will be delivered in one envelope to certain stockholders having the same last name and address and to individuals with more than one account registered at our transfer agent with the same address, unless contrary instructions have been received from an affected stockholder, a practice commonly referred to as “householding.” Stockholders participating in householding will continue to receive separate proxy cards. We will promptly deliver, upon written or oral request, individual copies of the proxy materials to any stockholder at the shared address to which single copies of those documents were delivered. If you are a stockholder of record and would like to enroll in this householding service or would like to receive individual copies of this year’s and/or future proxy materials, please contact our General Counsel and Secretary by mail at One Allison Way, Indianapolis, Indiana 46222 or by phone at (317) 242-5000. If you are a beneficial owner, you may contact the broker or bank where you hold the account to enroll in this householding service or to receive individual copies of this year’s and/or future proxy materials.

Could other matters be decided at the Annual Meeting?

As of the date of this proxy statement, our Board is not aware of any matters, other than those described in this proxy statement, which are to be voted on at the Annual Meeting. If any other matters are properly raised at the Annual Meeting, however, the persons named as proxy holders intend to vote the shares represented by your proxy in accordance with their judgment on such matters.

What is Allison’s Internet address?

Our Internet address is http://www.allisontransmission.com. You can access this proxy statement, form of proxy card and our 2018 Annual Report to Stockholders at this Internet address. Allison’s filings with the SEC are available free of charge via a link from this address or directly from the SEC’s website at www.sec.gov. Unless expressly indicated otherwise, information contained on, or accessible through, our website is not a part of this proxy statement. In addition, none of the information on the other websites listed in this proxy statement is a part of this proxy statement. These website addresses are intended to be inactive textual references only.

Policies on Corporate Governance

Our Board believes that good corporate governance is important to ensure our business is managed for the long-term benefit of our stockholders. We have adopted a Code of Business Conduct that applies to all directors, officers and other employees. Our Board has adopted Corporate Governance Guidelines, which, in conjunction with our Second Amended and Restated Certificate of Incorporation, Bylaws and Board committee charters, form the framework for our corporate governance. The current version of the Code of Business Conduct, our Board’s Corporate Governance Guidelines and the charters for each of the Audit Committee, Compensation Committee, Finance Committee and Nominating and Corporate Governance Committee are available in the Investor Relations section of our website, www.allisontransmission.com. We will post on the Investor Relations section of our website any amendment to, or waiver from, a provision of the Code of Business Conduct that applies to any of our directors or executive officers. Our Board regularly reviews corporate governance developments and modifies its Corporate Governance Guidelines, committee charters and key practices as warranted.

Board Leadership Structure

Since 2007, Lawrence E. Dewey has served as Chair of the Board. Effective on June 1, 2018, David S. Graziosi succeeded Mr. Dewey as our Chief Executive Officer, or CEO. Our Board believes that continuing to have Mr. Dewey fill the role of Chair of the Board is an appropriate and efficient leadership structure during this time of transition to a new CEO. Because Mr. Dewey is not independent, our Board has designated Thomas W. Rabaut as Lead Independent Director to serve as chairman of executive sessions of the independent directors, calling meetings of the independent directors and communicating the results of such meetings to the Chair of the Board, facilitating communication and serving as a liaison between the independent directors and the Chair of the Board and between the independent directors and management, reviewing and approving, in connection with the Chair of the Board, all agendas for meetings of the Board and communicating with major stockholders upon request. Our Board re-evaluates our leadership structure on an ongoing basis and may change it as circumstances warrant.

Board Role in Risk Oversight

While risk management is primarily the responsibility of our management, our Board provides overall risk oversight focusing on the most significant risks facing us. Our Board oversees the risk management processes that have been designed and are implemented by our executives to determine whether those processes are functioning as intended and are consistent with our business and strategy. Our Board executes its oversight responsibility for risk management directly and through its committees. Our Board’s role in risk oversight has not affected its leadership structure.

The Audit Committee is specifically tasked with overseeing our compliance with legal, ethical and regulatory requirements, discussing our major financial risk exposures, including our risk assessment and risk management processes, with management and receiving information on material legal and regulatory affairs. Our Managing Director, Financial and Tax Reporting coordinates our enterprise risk management process, and the Audit Committee receives regular reports regarding our enterprise risk management process. The Compensation Committee is tasked with overseeing our compensation-related risk assessment. See “Executive Compensation—Compensation-Related Risk Assessment” below. Our Board’s other committees oversee risks associated with their respective areas of responsibility.

The full Board considers specific risk topics, including risk-related issues pertaining to laws and regulations enforced by the United States and foreign government regulators and risks associated with our business plan and capital structure. In addition, our Board receives reports from members of our management that include discussions of the risks and exposures involved with their respective areas of responsibility. Further, our Board is routinely informed of developments that could affect our risk profile or other aspects of our business.

Director Independence

Our Board’s Corporate Governance Guidelines, which are available on our website as described above, require that our Board be comprised of a majority of directors who qualify as independent directors under the listing standards of the New York Stock Exchange, or NYSE. Our Board has determined that each of the following non-employee directors is independent under the listing standards of the NYSE: Judy L. Altmaier, Stan A. Askren, David C. Everitt, Alvaro Garcia-Tunon, William R. Harker, Carolann I. Haznedar, Richard P. Lavin, Thomas W. Rabaut and Richard V. Reynolds. Our Board has determined that directors Lawrence E. Dewey, who was our employee until June 1, 2018, and David S. Graziosi, who is currently our employee, are not independent.

Majority Vote Standard for Election of Directors

Our Bylaws require directors to be elected by the majority of the votes cast with respect to that director in uncontested elections (the number of shares voted “for” a director must exceed the number of votes cast “against” that director). In a contested election (a situation in which the number of nominees exceeds the number of directors to be elected), the standard for election of directors will be a plurality of the shares represented in person or by proxy at any such meeting and entitled to vote on the election of directors. If a nominee who is serving as a director is not elected at the Annual Meeting, under Delaware law the director would continue to serve on the Board as a “holdover director.” However, under our Corporate Governance Guidelines, any director who fails to be elected must tender his or her resignation to the Board. The Nominating and Corporate Governance Committee would then make a recommendation to the Board whether to accept or reject the resignation, or whether other action should be taken. The Board will act on the Nominating and Corporate Governance Committee’s recommendation and publicly disclose its decision and the rationale behind it within 90 days from the date the election results are certified. The director who tenders his or her resignation will not participate in the Board’s decision. If a nominee who was not already serving as a director is not elected at the Annual Meeting, under Delaware law that nominee would not become a director and would not serve on the Board as a “holdover director.”

Nominations for Directors

The Nominating and Corporate Governance Committee considers director nominees recommended by stockholders using the same criteria to evaluate candidates received from other sources. See “—Director Qualifications” below. A stockholder who wishes to recommend a director candidate for consideration by the Nominating and Corporate Governance Committee should send the recommendation to our General Counsel and Secretary at One Allison Way, Indianapolis, Indiana 46222, who will then forward it to the Nominating and Corporate Governance Committee. Any recommendation should include a description of the candidate’s qualifications for Board service, the candidate’s written consent to be considered for nomination and to serve if nominated and elected, and addresses and telephone numbers for contacting the stockholder and the candidate for more information. A stockholder who wishes to nominate an individual as a candidate for election at an annual meeting, rather than recommend the individual to the Nominating and Corporate Governance Committee as a nominee, or include a director nominee in our proxy statement, must comply with the advance notice requirements or our proxy access requirements set forth in our Bylaws and provide the information required by our Bylaws regarding the nominee, the stockholder of record and the beneficial owner, if any. See “Stockholder Proposals at 2020 Annual Meeting” for more information on these procedures. During 2018, we engaged the National Association of Corporate Directors, or NACD, to conduct a search for qualified director candidates. Messes. Haznedar and Altmaier were identified through the NACD search process. Ms. Haznedar was appointed to our Board in November 2018 and Ms. Altmaier was appointed to our Board in February 2019.

Director Qualifications

In considering candidates for our Board, the Nominating and Corporate Governance Committee considers the entirety of each candidate’s credentials and does not have any specific minimum qualifications that must be met by a committee-recommended nominee, but may consider the following criteria, among others: personal and professional integrity, ethics and values; experience in corporate management, such as serving as an officer or former officer of a publicly-held company; experience in our industry and with relevant social policy concerns; experience as a board member of another publicly-held company; academic expertise in an area of our operations; practical and mature business judgment, including the ability to make independent analytical inquiries; ownership of our stock; and gender and racial diversity. The Nominating and Corporate Governance Committee

and our Board evaluate each individual in the context of our Board as a whole, with the objective of assembling a group that can best perpetuate the success of the business and represent stockholder interests through the exercise of sound judgment using its diversity of experience in these various areas.

Our Board is committed to actively seeking qualified candidates who reflect diverse backgrounds, including diversity of gender and race. Our Corporate Governance Guidelines and the Nominating and Corporate Governance Committee charter require diverse candidates to be considered in each search for new Board nominees. Our Board recommends candidates based on the diversity of their business or professional experience, background, talents and perspectives. Our Board considers diversity in the context of the Board as a whole and takes into account the personal characteristics, including gender, ethnicity, age, experience, including financial expertise, and educational and professional background, of current and prospective directors. Our Board believes this process will best facilitate Board deliberations that reflect a broad range of perspectives and lead to a more effective decision-making process.

The following chart highlights each director nominee’s specific skills, knowledge and experience. A lack of a mark does not mean the director nominee does not possess that qualification or skill; rather, a mark indicates a specific area of focus or expertise on which our Board relies most heavily. Each director nominee’s biography describes these qualifications and relevant experience in more detail.

Stockholder Communication with our Board

Our Board has implemented a process whereby our stockholders and all interested parties may send communications to our Board’s attention. Any stockholder or interested party desiring to communicate with our Board, or one or more specified members thereof, should communicate (i) in writing addressed to Allison Transmission Holdings, Inc., Board of Directors, Attention: General Counsel and Secretary, One Allison Way, Indianapolis, Indiana 46222, (ii) via email at stockholders@allisontransmission.com or (iii) via telephone at +1.317.242.4425. Our Board has instructed our General Counsel and Secretary to promptly forward all such communications to the specified addressees thereof. With respect to correspondence received by the Company that is addressed to one or more directors, the Board has requested that the following items not be distributed to directors because they generally fall into the purview of management, rather than the Board: junk mail and mass mailings, service complaints and inquiries, resumés and other forms of job inquiries, solicitations for charitable donations, surveys, business solicitations, and advertisements.

Our Board has adopted a written policy for the evaluation of, and the approval, disapproval and monitoring of, transactions involving us and “related persons.” For purposes of the policy, “related persons” include our executive officers, directors and director nominees or their immediate family members, or stockholders owning five percent or more of our outstanding common stock and their immediate family members.

The policy covers any transaction, arrangement or relationship, or any series of similar transactions, arrangements or relationships, in which we were or are to be a participant, the amount involved exceeds $120,000 and a related person had or will have a direct or indirect material interest. Pursuant to this policy, our management presents to our Nominating and Corporate Governance Committee each proposed related person transaction, including all relevant facts and circumstances relating thereto. Our Nominating and Corporate Governance Committee then:

All related person transactions may only be consummated if our Nominating and Corporate Governance Committee has approved or ratified such transaction in accordance with the guidelines set forth in the policy. Certain types of transactions have been pre-approved by our Nominating and Corporate Governance Committee under the policy. These pre-approved transactions include:

(i) his or her position as a director of another entity that is party to the transaction;

(ii) an equity interest of less than 10% in another entity that is party to the transaction; or

(iii) a limited partnership interest of less than 10%, subject to certain limitations;

No director may participate in the approval of a related person transaction for which he or she is a related person.

Sales to Customers Indirectly Owned by Director

During 2018, we had net sales of less than $25 million to Gillig LLC, or Gillig, and less than $5 million to General Dynamics Corporation, or GD. Pursuant to information provided to us by James A. Star in connection with the preparation of our proxy statement for our 2018 annual meeting of stockholders, Mr. Star, a member of our Board until May 2018, had an indirect material interest in Gillig as a result of trusts for the benefit of his wife and children collectively owning an approximately 5% interest in the entities that directly and indirectly own Gillig. In addition, all of the remaining direct and indirect interests in Gillig were owned by trusts for the benefit of members of Mr. Star’s wife’s immediate and extended family. Mr. Star also reported having an indirect material interest in GD as a result of trusts for the benefit of his wife, children and members of his wife’s immediate and extended family collectively owning approximately 10% of the outstanding shares of common stock of GD.

Board Composition

Our Board currently consists of eleven members. Lawrence E. Dewey, our former CEO, is Chair of the Board, and Thomas W. Rabaut is Lead Independent Director. The exact number of members on our Board may be modified from time to time exclusively by resolution of our Board.

Board Meetings, Attendance and Executive Sessions

Our Board meets on a regularly scheduled basis during the year to review significant developments affecting us and to act on matters requiring Board approval. It also holds special meetings when an important matter requires Board action between scheduled meetings. Members of senior management regularly attend meetings of our Board and its committees to report on and discuss their areas of responsibility. Directors are expected to attend Board meetings, meetings of committees on which they serve and stockholder meetings. During 2018, our Board held six meetings and committees of our Board held a total of 20 meetings. All directors attended 75% or more of the meetings of our Board and committees on which they served that were held during the period for which he or she was a director or committee member. All of our current directors who were serving as directors or nominated to serve as a director at the time of our 2018 annual meeting of stockholders attended that meeting.

Each regularly scheduled Board meeting normally concludes with a session between our CEO and the other directors. This provides a platform for discussions outside the presence of the non-Board management attendees, as well as an opportunity for the independent directors to go into executive session (without the CEO and Chair) if requested by any director. The independent directors may meet in executive session, without the Chair, at any time, and are scheduled for such non-independent executive sessions at each regularly scheduled Board meeting. As Lead Independent Director, Mr. Rabaut presides at executive sessions of independent directors.

Board Committees

Our Board directs the management of our business and affairs as provided by Delaware law and conducts its business through meetings of our Board and four standing committees: the Audit Committee, the Compensation Committee, the Nominating and Corporate Governance Committee and the Finance Committee. In addition, from time to time, other committees may be established under the direction of our Board when necessary to address specific issues. The table below shows the current membership of each Board committee and the number of meetings held during 2018:

The membership of the Audit Committee, Compensation Committee and Nominating and Corporate Governance Committee is composed entirely of independent directors and meets the heightened standards of independence for audit committee and compensation committee members, respectively, required by SEC rules and NYSE listing standards.

The Audit Committee

The Audit Committee oversees our accounting and financial reporting processes and the audits of our consolidated financial statements provided by us to any governmental body or the public, and prepares the report of the Audit Committee included under “Report of the Audit Committee” in this proxy statement. The Audit Committee also assists our Board in discharging its oversight responsibilities regarding the integrity of our consolidated financial statements, our compliance with legal, ethical and regulatory requirements, the qualifications and independence of our independent registered public accounting firm and the performance of our internal audit function. The Audit Committee has sole authority to appoint, subject to stockholder ratification, or replace our independent registered public accounting firm and pre-approves the auditing services and permitted non-audit services to be performed by our independent registered public accounting firm, including the fees and terms thereof. The Audit Committee reviews and discusses with management and our independent registered public accounting firm our annual audited consolidated financial statements, our quarterly earnings releases and financial statements, and significant financial reporting issues and judgments made in connection with the preparation of our financial statements. The charter of the Audit Committee requires that each member meet the independence and experience requirements of the NYSE, the Securities Exchange Act of 1934, as amended, or the Exchange Act, and the rules and regulations of the SEC.

Our Board has determined that Alvaro Garcia-Tunon qualifies as an “audit committee financial expert” as defined by SEC rules.

The Compensation Committee

The Compensation Committee (i) reviews, approves and/or oversees compensation provided to our executive officers and employees and all agreements and arrangements with respect thereto, (ii) establishes our general compensation policies and (iii) reviews, approves and/or oversees the administration of our employee benefits plans and makes recommendations for stockholder approval of such plans, as applicable.

The Compensation Committee may take into consideration the recommendations of our Chief Executive Officer with respect to the compensation of our other executive officers. The Compensation Committee also discusses with management the Compensation Discussion and Analysis, and, if appropriate, recommends its inclusion in our annual report on Form 10-K and proxy statement and issues the report on its activities which appears under “Executive Compensation—Compensation Committee Report” in this Proxy Statement. The charter of the Compensation Committee requires that each member meet the independence requirements of the NYSE and the rules and regulations of the SEC.

The Compensation Committee has authority to retain the advice and assistance of independent counsel, compensation consultants or other experts or consultants. For 2018, the Compensation Committee retained Semler Brossy Consulting Group, LLC, or Semler Brossy, as its compensation consultant. See “Executive Compensation—Compensation Discussion and Analysis—Compensation Overview—Role of Compensation Consultant” for a description of the services provided to the Compensation Committee by Semler Brossy.

The Nominating and Corporate Governance Committee

The Nominating and Corporate Governance Committee assists our Board in discharging our Board’s responsibilities regarding identifying qualified candidates to become Board members, selecting nominees for election as directors at our annual meetings of stockholders, selecting candidates to fill any vacancies on our Board and overseeing the evaluation of our Board. See “Corporate Governance—Nominations for Directors” and “—Director Qualifications” above for additional information. The Nominating and Corporate Governance Committee approves compensation provided to our directors and all related person transactions. The Nominating and Corporate Governance Committee has the authority to retain any independent counsel, experts or advisors. The charter of the Nominating and Corporate Governance Committee requires that all responsibilities of such committee required under NYSE rules to be performed by directors who satisfy the independence requirements of the NYSE be performed solely by the members of such committee who qualify as independent.

The Finance Committee

The Finance Committee assists our Board in discharging our Board’s responsibilities regarding significant transactions, including strategic investments, mergers and acquisitions and divestitures, capital expenditures, capital structure, including dividends, stock repurchases and borrowing and equity practices, and other financial strategies and special projects. The Finance Committee has the authority to retain any independent counsel, experts or advisors.

Compensation Committee Interlocks and Insider Participation

During fiscal year 2018, our Compensation Committee consisted of General Reynolds and Messrs. Askren, Lavin and Star through May 9, 2018 and General Reynolds and Messrs. Askren, Harker and Lavin after May 9, 2018. None of the members of our Compensation Committee during 2018 or as of the date of this proxy statement is or has been one of our officers or employees. During fiscal year 2018, none of our executive officers served as a member of the board of directors or compensation committee, or other committee serving an equivalent function, of any entity that has one or more executive officers who serve as members of our Board or our Compensation Committee. During 2018, we had sales to Gillig and GD, each of which may be deemed to be indirectly owned or controlled by Mr. Star as a result of the ownership interests in each of these companies held by trusts for the benefit of his wife, children and members of his wife’s immediately family. See “Certain Relationships and Related Person Transactions—Sales to Customers Indirectly Owned by Director” above for additional information.

Security Ownership of Certain Beneficial Owners

The following table sets forth certain information concerning each person (including any group) known to us to beneficially own more than five percent (5%) of our common stock as of March 11, 2019.

Security Ownership of Directors and Officers

The following table sets forth information with respect to the beneficial ownership of our common stock as of the close of business on March 11, 2019 by each of our directors, nominees for director and named executive officers, as well as all of our directors and executive officers as a group.

The amounts and percentages of shares beneficially owned are reported on the basis of SEC regulations governing the determination of beneficial ownership of securities. Under SEC rules, a person is deemed to be a “beneficial” owner of a security if that person has or shares voting power or investment power, which includes the power to dispose of or to direct the disposition of such security. A person is also deemed to be a beneficial owner of any securities of which that person has a right to acquire beneficial ownership within 60 days. Securities that can be so acquired are not deemed to be outstanding for purposes of computing any other person’s percentage. Under these rules, more than one person may be deemed to be a beneficial owner of securities as to which such person has no economic interest.

Except as otherwise indicated in these footnotes, each of the directors and officers listed has, to our knowledge, sole voting and investment power with respect to the shares of common stock. None of the shares owned by our directors and executive officers have been pledged as security.

Section 16(a) Beneficial Ownership Reporting Compliance

Section 16(a) of the Exchange Act requires our directors, executive officers and beneficial owners of more than 10% of our capital stock to file reports of ownership and changes of ownership with the SEC and NYSE. Based on our records and other information, we believe that during the year ended December 31, 2018, all applicable Section 16(a) filing requirements were met.

The following table provides information regarding our executive officers as of March 11, 2019.

David S. Graziosi

Mr. Graziosi’s biographical information is included under “Proposal No. 1—To elect eleven directors.”

G. Frederick Bohley

Mr. Bohley serves as Vice President, Chief Financial Officer and Treasurer, a position he has held since June 2018. Mr. Bohley began his career at Allison Transmission in 1991 with the Finance department where he held positions of increasing responsibility, including General Accountant, Tax Specialist, Internal Auditor, Plant Analyst, Manager of Manufacturing Analysis, and Manager of Financial Planning and Analysis. In 2001, Mr. Bohley joined Marketing, Sales and Service where he held the position of National Account Executive. In 2003, he relocated to Sao Paulo, Brazil as Director of Latin American Operations and he returned in 2006 as Director of International Marketing and Business Planning. In October 2007, following Allison’s divestiture from General Motors, Mr. Bohley rejoined the Finance department and was promoted to Executive Director of Financial Planning and Analysis, Pricing and International Finance. He added Investor Relations to his responsibilities in January 2013 and Business Planning in August 2014. He was promoted to Vice President, with the added responsibility of the treasury department, in March 2016 and became Treasurer in July 2017. Mr. Bohley holds a bachelor’s degree in business, with majors in accounting and finance, from the Kelley School of Business at Indiana University.

John M. Coll

Mr. Coll joined Allison as Senior Vice President, Global Marketing, Sales and Service in October 2016. Prior to joining Allison, Mr. Coll was Vice Present of Sales and Marketing at Gerdau Ameristeel U.S. from January 2015 to October 2016. Prior to that, Mr. Coll served fourteen years at Eaton Corporation, or Eaton, most recently as Vice President of Global Marketing for the vehicle group from January 2011 to January 2015. Prior to that, he held a number of other roles at Eaton, including Director of Global Channel Marketing for Eaton Electrical, General Manager of Aftermarket and Vehicle Solutions for Truck Components and Vice President of Sales and Marketing for Truck Components. Prior to joining Eaton, Mr. Coll served thirteen years at Philips Electronics in a variety of sales and distributor relations roles. Mr. Coll earned a bachelor’s degree in business administration from West Virginia University and a Master of Business Administration from the University of Pittsburgh.

Michael A. Dick

Mr. Dick has served as Senior Vice President of Operations and Purchasing since January 2016, with worldwide responsibility for manufacturing, global supply chain, manufacturing engineering and facilities. He had most recently been Vice President of Purchasing, Supplier Quality and Manufacturing Engineering since August 2012. Mr. Dick joined Allison Transmission in July 2006 and previously served in two other key executive positions. As Executive Director of Operations and Plant Manager for the 1000/2000 Series™ manufacturing facility in

Indianapolis, a position Mr. Dick held from July 2006 through December 2007, his team significantly improved in the manufacturing cost per unit, hours per unit, customer pulls and customer complaint parts per million (PPM). As Executive Director of Manufacturing Engineering, a position he held from January 2008 through July 2012, Mr. Dick and the manufacturing engineering team were responsible for the successful launch of the assembly plant in Chennai, India and the relocation of the 3000/4000 Series™ assembly operations to Szentgotthárd, Hungary. Prior to joining Allison, Mr. Dick worked for the New Venture Gear Corp. (a joint venture between General Motors and Chrysler) where he served as the Vice President and Division Manager. In this role, he and his team took a business that had been losing money for a decade and made it profitable. Mr. Dick holds a bachelor’s degree in mechanical engineering technology from Purdue University.

Randall R. Kirk

Mr. Kirk joined Allison in May 1976 and serves as Senior Vice President, Product Engineering and Product Teams, a position he has held since August 2014. At the beginning of his career at Allison, he served in a number of roles with increasing responsibility in the Operations and Quality organizations, including Supervisor, General Supervisor, Production Superintendent, Quality/Reliability Manager, and a dual role as Manager of Manufacturing Engineering and Quality and Divisional Program Manager. From 1997 until 2001, Mr. Kirk assumed the responsibilities of Product Team Leader for several product lines. He then served as Director of Customer Support in Marketing, Sales and Service from 2001 until 2007. From 2007 until 2009, Mr. Kirk was Executive Director of the Transition Program Manager Office, leading a cross-functional team with responsibilities for the separation from General Motors. Following the divestiture in 2009, he was appointed as Vice President, Product Engineering before his promotion to Senior Vice President, Product Engineering and Product Teams in August 2014.

Dana J.H. Pittard

Mr. Pittard joined Allison Transmission in October 2015 as Deputy Vice President of Defense Programs. He was promoted to Vice President, Defense Programs in January 2016. Mr. Pittard retired from the U.S. Army in the grade of Major General (2 Star) after 34 years of active duty. He has commanded Armor and Infantry units at every level from platoon to Division, including command of the 1^st Armored Division. His service included multiple combat tours. Mr. Pittard brings a wealth of experience in combat vehicle technology and a deep understanding of the Department of Defense and congressional budget processes. He served as the Director of Operations for the Army Training and Doctrine Command, the organization responsible for defining requirements for combat vehicles. As the commander of Fort Bliss, Texas from 2010 to 2013, he transformed the post into one of the largest operational training installations in the Army, and was responsible for a community of over 100,000 soldiers, civilians and family members.

Eric C. Scroggins

Mr. Scroggins joined Allison as Vice President, General Counsel and Secretary in December 2007 and has served in that position since then. He is responsible for advising our Board and leadership team on legal and business matters, managing our legal affairs and overseeing our Export Compliance, Corporate Affairs and Communications and Internal Audit organizations. Prior to joining Allison, Mr. Scroggins served as General Counsel for Product Action International, LLC and was an attorney with the law firm of Ice Miller LLP. Prior to joining Ice Miller LLP, Mr. Scroggins worked for the State of Indiana, serving in various roles with the Indiana State Personnel Department, including Deputy Director.

Our Board currently consists of eleven directors serving one-year terms until the next annual meeting of stockholders and until the director’s successor is elected and has qualified. Based upon the recommendation of our Nominating and Corporate Governance Committee, our Board has nominated eleven directors to be elected to our Board. Proxies cannot be voted for a greater number of persons than the eleven director nominees.

Unless indicated otherwise, it is the intention of the persons named in the accompanying proxy card to vote such proxy for the election to our Board of Judy L. Altmaier, Stan A. Askren, Lawrence E. Dewey, David C. Everitt, Alvaro Garcia-Tunon, David S. Graziosi, William R. Harker, Carolann I. Haznedar, Richard P. Lavin, Thomas W. Rabaut and Richard V. Reynolds. All of the nominees for director currently serve on our Board. Each of the nominees for director has consented to being named as a nominee in this proxy statement and has indicated a willingness to serve if elected. However, if any such person is unable or unwilling to accept nomination or election, it is the intention of the persons named in the accompanying proxy card to nominate such other person as director as they may in their discretion determine, in which event the shares will be voted for such other person. If for any reason a nominee should become unable or unwilling to accept nomination or election, the proxy holders intend to vote the proxy for the election of such other person as our Board, upon the recommendation of the Nominating and Corporate Governance Committee, may select. Alternatively, our Board may reduce the number of directors to eliminate the vacancy.

The information set forth below states the name of each nominee for director, his or her age, a listing of present and previous employment positions, the year in which he or she first became a director of the Company, other public company directorships held and the key qualifications, experiences, attributes or skills that led to the conclusion that he or she should serve as a director. There is no family relationship among any of our directors, nominees for director or executive officers.

Nominees for Director

	Judy L. Altmaier, Director since February 2019
	Ms. Judy L. Altmaier, age 57, served as the President of Exmark Manufacturing Co, a subsidiary of The Toro Company, from 2013 until her retirement in January 2019. Prior to that, she was Vice President, Operations and Quality Management of The Toro Company, or Toro, from 2009 until 2013. Before joining Toro, Ms. Altmaier spent more than 25 years with Eaton, holding positions of increasing responsibility including Vice President of Operations, Auto Group Americas during 2009 and Vice President, General Manager Global Engine Valve Division in Turin, Italy from 2007 until 2009. Ms. Altmaier joined Eaton in 1983 as an accountant.
	Our Board has concluded that Ms. Altmaier should serve as director because of her industry experience in manufacturing, operations, supply chain management, mergers and acquisitions and product development and strategy, including in the areas of automation and electrification, developed over her career with the Toro Company and Eaton. In addition, Ms. Altmaier brings significant experience in international operations and execution of growth initiatives to our Board.
	Stan A. Askren, Director since March 2016
	Mr. Stan A. Askren, age 58, is currently CEO and Founder of Quiet Trail Advisors, a private, senior level strategy and lean business advisory practice. He serves as an advisor and lean business consultant for Lean Focus, LLC. Mr. Askren served as the chairman of HNI Corporation, or HNI, from 2004 until his retirement on December 31, 2018 and as CEO of HNI from 2004 until July 2018. Previously, he was the president of HNI from 2003 to April 2018, and executive vice president of HNI from 2001 to 2003. Mr. Askren had worked at HNI for 27 years, including as vice president of marketing, vice president of human resources, and as an executive vice president and president of HNI’s hearth business segment. Mr. Askren has also worked in several industries and previously held multiple executive management and general management positions with Emerson Electric, Thomson S.A. and HNI.
	Mr. Askren has been a director of Armstrong World Industries, Inc. since 2008 and served as a director of Arctic Cat Inc. from 2012 to 2014 and of HNI from 2003 until 2018. Mr. Askren formerly served on the board of directors of the Iowa Heritage Foundation, the Business and Institutional Furniture Manufacturer’s Association (past chair) and the Iowa Business Council (past chair).
	Our Board has concluded that Mr. Askren should serve as director because of his experience gained from his positions as President and Chief Executive Officer of HNI, along with his broad-based experience in human resources, operations, marketing and multi-channel sales. Mr. Askren has been recognized as an expert in lean operations and business practice. In addition he has extensive director experience from his service on the boards of HNI, Arctic Cat Inc. and Armstrong World Industries, Inc.

The Audit Committee has selected PricewaterhouseCoopers LLP, or PwC, as our independent registered public accounting firm for 2019. Stockholders have the opportunity to ratify that selection in an advisory, non-binding vote.

The Audit Committee approves all audit and permissible non-audit services to be provided to us by PwC prior to commencement of services. The Audit Committee has delegated to the Chairman of the Audit Committee the authority to approve specific services up to specified individual and aggregate fee amounts. These approval decisions are presented to the full Audit Committee at the next scheduled meeting after such approvals are made.

We have incurred fees for services from PwC in the below-indicated amounts for the following categories of services for the years ended December 31, 2018 and 2017, respectively:

We expect that representatives of PwC will be present at the Annual Meeting, will have an opportunity to make a statement if they desire to do so and will be available to respond to appropriate questions.

The Audit Committee of our Board has the sole authority to appoint, replace, compensate and oversee the independent auditor, and shall pre-approve the fees and other terms of all engagements for audit and non-audit services provided by the independent auditor. In 2018, all of the Company’s audit fees paid to the independent auditor were pre-approved by the Audit Committee.

If the holders of a majority of the voting power of the shares entitled to vote on this proposal represented in person or by proxy do not approve the proposal, the Audit Committee will reconsider its choice, taking into consideration the views of the stockholders, and may, but will not be required to, appoint a different independent registered public accounting firm.

The Audit Committee is responsible for monitoring the integrity of the Company’s consolidated financial statements, the qualifications, performance and independence of the independent registered public accounting firm, the performance of the Company’s internal auditor and compliance with legal and regulatory requirements. The Audit Committee is directly responsible for the appointment, compensation, retention and oversight of the work of the independent registered public accounting firm.

Management is responsible for the financial reporting process, including the system of internal control, for the preparation of consolidated financial statements in accordance with accounting principles generally accepted in the United States and for management’s report on internal control over financial reporting. The independent registered public accounting firm is responsible for auditing the consolidated financial statements and expressing an opinion as to their conformity with accounting principles generally accepted in the United States, as well as auditing the effectiveness of the Company’s internal control over financial reporting as of December 31, 2018. The Audit Committee’s responsibility is to oversee and review the financial reporting process and to review and discuss management’s report on internal control over financial reporting. We are not, however, professionally engaged in the practice of accounting or auditing and do not provide any expert or other special assurance as to such consolidated financial statements concerning compliance with laws, regulations or accounting principles generally accepted in the United States or as to the independence of the independent registered public accounting firm. We rely, without independent verification, on the information provided to us and on the representations made by management and the independent registered public accounting firm.

We held eight meetings during 2018. The meetings were designed, among other things, to facilitate and encourage communication among the committee, management, the internal auditor and the independent registered public accounting firm, PricewaterhouseCoopers LLP, or PwC.

We discussed with the internal auditor and PwC the overall scope and plans for their respective audits. We met with the internal auditor and PwC, with and without management present, to discuss the results of their examinations and their evaluations of the Company’s internal control over financial reporting. We reviewed and discussed the Company’s compliance with Section 404 of the Sarbanes-Oxley Act of 2002.

We discussed with management the Company’s major financial risk exposures and the steps management has taken to monitor and control such exposures, including risk assessment and risk management processes.

We reviewed and discussed the audited consolidated financial statements for the year ended December 31, 2018 with management, the internal auditor and PwC and reviewed and discussed with management, the internal auditor and PwC management’s report on internal control over financial reporting. We reviewed PwC’s report on the Company’s consolidated financial statements, which indicated that the consolidated financial statements present fairly, in all material respects, the Company’s financial position and results of operations and cash flows in conformity with accounting principles generally accepted in the United States and PwC’s audit of the effectiveness of the Company’s internal control over financial reporting as of December 31, 2018. We also discussed with management, the internal auditor and PwC the process used to support certifications by the Company’s Chief Executive Officer and Chief Financial Officer that are required by the Securities and Exchange Commission and the Sarbanes-Oxley Act of 2002 to accompany the Company’s periodic filings with the Securities and Exchange Commission and the process used to support management’s report on internal control over financial reporting.

We also discussed with PwC all matters required to be discussed by their professional standards, including, among other things, matters related to the conduct of the audit of the Company’s consolidated financial statements and the matters required to be discussed pursuant to applicable Public Company Accounting Oversight Board, or PCAOB, standards.

PwC provided us with the written disclosure and the letter required by applicable PCAOB requirements and represented that PwC is independent from the Company. We discussed with PwC its independence from the Company. When considering PwC’s independence, we considered if services they provided to the Company beyond those rendered in connection with their audit of the Company’s consolidated financial statements, reviews of the Company’s quarterly unaudited consolidated financial statements and review of the Company’s internal control over financial reporting, were compatible with maintaining their independence. We concluded that the provision of such services by PwC has not jeopardized PwC’s independence.

Based on our review and these meetings, discussions and reports, and subject to the limitations on our role and responsibilities referred to above and in the Audit Committee Charter, we recommended to our Board, and our Board approved, that the Company’s audited consolidated financial statements for the year ended December 31, 2018 be included in the Company’s Annual Report on Form 10-K. We have also selected PwC as the Company’s independent registered public accounting firm for the year ended December 31, 2019 and will present the selection to the stockholders for ratification at the Annual Meeting.

The Audit Committee:

Alvaro Garcia-Tunon, Chair
Judy L. Altmaier
William R. Harker
Carolann I. Haznedar
Richard V. Reynolds

Our executive compensation program is designed to align executive pay with our performance on both short-term and long-term bases, link executive pay to specific, measurable results intended to create value for stockholders and utilize compensation as a tool to assist us in attracting and retaining the high-caliber executives that we believe are critical to our long-term success.

The Compensation Discussion and Analysis beginning on page 30 of this Proxy Statement describes our executive compensation program and the decisions made by the Compensation Committee during 2018 in more detail. We are requesting that stockholders cast a non-binding advisory vote to approve the compensation paid to our named executive officers as disclosed in this Proxy Statement. This vote is not intended to address any specific item of compensation, but rather the overall compensation of our NEOs and the philosophy, policies and practices described in this Proxy Statement.

Accordingly, we recommend that our stockholders vote FOR the following resolution at the Annual Meeting:

“RESOLVED, that the compensation paid to the Company’s named executive officers, as disclosed pursuant to Item 402 of Regulation S-K, including the Compensation Discussion and Analysis, compensation tables and narrative discussion is hereby APPROVED.”

As an advisory vote, this resolution will not be binding on us, our Board or our Compensation Committee. However, we expect that the Compensation Committee, which is responsible for designing and administering our executive compensation programs, will consider the outcome of the vote when making future compensation decisions for our named executive officers. This vote is being presented as required by the Dodd-Frank Wall Street Reform and Consumer Protection Act and Section 14A of the Exchange Act.

We are conducting an advisory vote on the frequency of future advisory votes on the compensation paid to our named executive officers at this Annual Meeting. See “Proposal No. 4—An advisory, non-binding vote on the frequency of future advisory votes on the compensation paid to our named executive officers.”

Section 14A of the Exchange Act also allows our stockholders to express their preference on the frequency of future advisory votes on the compensation paid to our named executive officers. Stockholders may indicate whether we should hold future advisory votes on the compensation paid to our named executive officers every (a) 1 year, (b) 2 years or (c) 3 years, or stockholders may abstain from voting. We are required to hold this vote at least once every six calendar years, and the last vote on this topic was held in 2013. The next time we are required to conduct a similar vote would be in connection with the 2025 annual meeting of stockholders.

In 2013, our stockholders expressed a preference that we hold future advisory votes on the compensation paid to our named executive officers every three years. Consistent with that preference, since that time, we have held advisory votes on the compensation paid to our named executive officers every three years. At this time, and in response to feedback received from our stockholders, our Board feels that more regular advisory votes on the compensation paid to our named executive officers would be an improvement to our corporate governance practices and is consistent with market practice. As a result, the Board is recommending that our stockholders vote to hold future advisory votes on the compensation paid to our named executive officers annually, believing that this will result in better communication with stockholders and will result in more meaningful and direct input by stockholders into our executive compensation program, policies and practices, consistent with our policy of seeking input from, and engaging in discussions with, our stockholders on executive compensation and corporate governance matters. Stockholders are not being asked to approve or disapprove of the Board’s recommendation, but rather to indicate their own choice from among the frequency alternatives.

The option of every 1 year, 2 years, or 3 years that receives the highest number of votes cast by our stockholders will be considered our stockholders’ preferred frequency for conducting future advisory votes on the compensation paid to our named executive officers. However, because this vote is advisory and not binding on our Board or the Company, the Board may decide that it is in the best interests of our stockholders and the Company to hold future advisory votes on the compensation paid to our named executive officers more or less frequently than the option preferred by our stockholders.

Compensation Discussion and Analysis

Executive Summary

This Compensation Discussion and Analysis provides an overview and analysis of (i) the elements comprising our compensation program for our named executive officers, which we refer to in this Compensation Discussion and Analysis as our NEOs; (ii) the material 2018 compensation decisions made under that program and reflected in the executive compensation tables that follow this Compensation Discussion and Analysis; and (iii) the material factors considered in making those decisions.

For the year ended December 31, 2018, our NEOs were:

We intend to provide our NEOs with compensation that is largely performance based. Our executive compensation program is designed to align executive pay with our performance on both short and long-term bases, link executive pay to specific, measurable results intended to create value for stockholders, and utilize compensation as a tool to assist us in attracting and retaining the high-caliber executives that we believe are critical to our long-term success.

2018 CEO and CFO Transition and Related Compensation Decisions.

On June 1, 2018, David Graziosi succeeded Mr. Dewey as our CEO, with Mr. Dewey remaining the Chair of the Board. In March 2018, in anticipation of this transition, the Compensation Committee approved an increase in Mr. Graziosi’s annual base salary to $800,000 and we entered into a severance and change in control agreement with Mr. Graziosi, both effective as of June 1, 2018. See “—Employment and Severance Arrangements—Graziosi Severance and Change in Control Agreement” below. In addition, Mr. Graziosi was awarded 292,022 performance units under our 2015 Equity Incentive Award Plan, or the 2015 Plan, on June 29, 2018. The number of performance units granted was based on a target value of $12 million. This is a front-loaded award that is intended to replace Mr. Graziosi’s annual equity awards for calendar years 2018, 2019 and 2020. The Compensation Committee does not intend to make any additional equity awards to Mr. Graziosi until 2021. This front-loaded award was calibrated to deliver aggregate value approximately equal to three-years of market-competitive annual equity grants, which is annualized to be $4 million per year over the next three years. Between 0% and 200% of the performance units are eligible to vest, with 50% of the award based on our adjusted free cash flow per share, and 50% of the award based on relative total stockholder return, or rTSR, as compared to an industry peer group. In each case, performance is measured for the period beginning on January 1, 2018 and ending on December 31, 2020. The performance units that become eligible to vest will vest in equal installments on each of January 1, 2021, 2022 and 2023, subject to Mr. Graziosi’s continued employment through the applicable vesting date. The vesting of these performance units will accelerate in connection with a qualifying termination of employment.

In determining the CEO compensation package for Mr. Graziosi, the Compensation Committee recognized that Allison is at an inflection point for the business and must focus on driving revenue growth, delivering on cash flow expansion, evaluating and realizing international opportunities, addressing potential technology disruption and maintaining our capital allocation policy. To support the business strategy and motivate Mr. Graziosi as CEO, the Compensation Committee designed the one-time, 100% performance-based equity grant, with the following objectives:

The Compensation Committee selected the adjusted free cash flow metric to ensure we have available resources to maintain and grow our business by effectively deploying cash for repayment of debt, funding stockholder distributions and other strategic opportunities, including investing in our business. The Compensation Committee determined to use a per share metric for adjusted free cash flow to ensure that we are effectively executing our stock repurchase strategy to deliver returns to stockholders. rTSR was selected because it aligns Mr. Graziosi’s compensation with the results for our stockholders and is the same metric used for the performance units awarded to our senior leadership team.

Also on June 1, 2018, Fred Bohley succeeded Mr. Graziosi as CFO. In May 2018, the Compensation Committee approved an increase in Mr. Bohley’s annual base salary to $375,000, an increase in Mr. Bohley’s target annual incentive compensation, or IComp, award to 100% of base salary and an increase in Mr. Bohley’s target annual long-term equity incentive award to 120% of base salary, each effective as of June 1, 2018. Because Mr. Bohley had received an annual equity award on February 7, 2018 at a lower target value for his prior role, Mr. Bohley received an additional grant of stock options, restricted stock units, or RSUs, and performance units on June 1, 2018, to bring the total target value of the equity awards received by Mr. Bohley in 2018 to 120% of his base salary as in effect on June 1, 2018. See “—2018 Compensation Decisions—Long-Term Equity Incentive Awards” below for details on Mr. Bohley’s awards.

2018 Business Results and Implications for Compensation. We achieved record level financial results and executed several key strategic priorities in 2018. Highlights include:

As a result of these accomplishments, our 2018 performance was 125% of target for purposes of our annual cash incentive bonus compensation program, which we refer to as IComp, resulting in a maximum payout of 250% of target. Adjusted EBITDA, Adjusted EBITDA as a percent of net sales and Gross adjusted free cash flow are non-GAAP financial measures. For information about how we define these measures and where to find a reconciliation to the most comparable GAAP measures, refer to the discussion below under the heading “—2018 Compensation Decisions—Annual Performance-Based Compensation.”

Our three-year total stockholder return, or TSR, for the period from 2016 through 2018 was strong at +76%, placing us at the 86^th percentile of our peer group, which resulted in a maximum payout of 200% of target for our 2016-2018 performance units. See “—2018 Compensation Decisions—Long-Term Equity Incentive Awards—Results of the 2016-2018 Performance Units” below.

Advisory Vote on Executive Compensation.

In 2013 our stockholders voted for future advisory votes on executive compensation to be held once every three years. Over 98% of the shares voted at our 2016 annual meeting of stockholders voted for our 2016 advisory vote on executive compensation, reflecting our stockholders’ strong support of our executive compensation program. Given the level of support received from our stockholders, we did not make any material changes to our executive compensation program as a result of this vote. At this Annual Meeting, our stockholders will be asked to vote on our executive compensation and the frequency of future advisory votes on executive compensation. See “Proposal No. 3—An advisory, non-binding vote to approve the compensation paid to our named executive officers” and “Proposal No. 4—An advisory, non-binding vote on the frequency of future advisory votes on the compensation paid to our named executive officers” above.

Corporate Governance Framework

We strive to maintain control and oversight of our executive compensation program through strong corporate governance. Specific examples of policies that we have adopted include:

Compensation Overview

Our overall compensation program is structured to attract, motivate and retain highly qualified executive officers by paying them competitively, with variable components to deliver pay results that are consistent with our success and their contribution to that success. We believe compensation should be structured to ensure that a significant portion of compensation opportunity is related to factors that directly and indirectly influence stockholder value. Accordingly, we set goals designed to link each NEO’s compensation to our performance and the NEO’s own performance.

We do not target a specific mix of compensation elements by executive, but our overall philosophy is to emphasize performance-based pay generally and long-term incentives, in particular. The following charts illustrate this emphasis for our CEO and other NEOs (excluding our former CEO Mr. Dewey), showing base salary, target annual cash incentive opportunity and target long-term incentive opportunity (which for Mr. Graziosi is one-third of the total target value of his performance units, which represents the intended annualized value of his award) as a percentage of target total direct compensation for 2018:

Compensation Elements. Compensation for our executive officers consists primarily of the elements, and their corresponding objectives, identified in the following table:

Our compensation decisions for the NEOs in 2018 are discussed below in relation to each of the above-described elements of our compensation program. The below discussion is intended to be read in conjunction with the executive compensation tables and related disclosures that follow this Compensation Discussion and Analysis.

Determination of Compensation Awards. The Compensation Committee is provided with the primary authority to establish and approve the compensation awards available to our executive officers and is charged with reviewing executive officer compensation policies and practices to ensure adherence to our compensation philosophies and that the total compensation paid to our executive officers is fair, reasonable and competitive. The Compensation Committee is primarily responsible for (i) establishing base salary and target bonus levels; (ii) assessing the performance of the CEO and other NEOs for each applicable performance period; (iii) approving the awards to be paid to our CEO and other NEOs under our annual IComp program for each year; and (iv) making equity award grants under our equity incentive compensation plan. To aid the Compensation Committee in making its determinations, the CEO provides recommendations to the Compensation Committee regarding the compensation of our other officers. The performance of our senior executive management team is reviewed by the Compensation Committee and the Compensation Committee approves each NEO’s compensation at least annually.

In establishing and approving compensation levels for our NEOs, the Compensation Committee considers each NEO’s unique position and responsibility and relies upon the judgment and experience of its members as well as the input of the Compensation Committee’s independent compensation consultant, including information regarding market practices. We believe that executive officer total compensation should be competitive with the compensation of executive officers in similar positions and with similar responsibilities in our marketplace, in consideration of financial and operating performance, each executive’s level of experience, and each executive’s current and expected future contributions to our results. In this regard, each executive officer’s current and prior compensation is considered as a reference point against which determinations are made as to whether increases are appropriate to retain the NEO in light of competition or in order to incent performance.

Role of Compensation Consultant. The Compensation Committee retained Semler Brossy as its independent compensation consultant for 2018. During 2018, Semler Brossy assisted the Compensation Committee with the following compensation-related matters:

In addition, in 2018 Semler Brossy assisted the Nominating and Corporate Governance Committee with evaluating Board compensation relative to market practices. Semler Brossy does not provide other services to our management. The Compensation Committee has assessed Semler Brossy’s independence and concluded that no conflict of interest exists that would prevent Semler Brossy from providing services to the Compensation Committee.

Use of Peer Group Data. The Compensation Committee reviews competitive pay practices in determining compensation for our executives, including our NEOs; however, the Compensation Committee does not target a specific percentile of market in determining individual pay levels. Rather, in alignment with the considerations described above under “—Determination of Compensation Awards,” the Compensation Committee determines the total amount of compensation for our NEOs, and the allocation of total compensation among each of our three main components of compensation — base salary, IComp and long-term equity incentives — in reliance upon the judgment and general knowledge of its members and the advice of the Compensation Committee’s independent consultant to ensure we attract, develop and retain superior talent.

The Compensation Committee reviewed peer group data provided by Semler Brossy in late 2017 for 2018 pay decisions for purposes of comparing our executive compensation programs and amounts to those of other publicly traded companies with size and financial characteristics similar to our own, or operating in similar industries. The peer group is reviewed annually based on U.S. publicly traded companies in the industrial components, parts and equipment industries, with a focus on companies similar in scale to Allison with comparable financial profiles (e.g., companies with EBITDA margins higher than 15%). For pay decisions made for 2018, our peer group consisted of the following companies:

In addition, the Compensation Committee included BorgWarner Inc., Cummins Inc., Eaton Corporation plc and Parker-Hannifin Corporation in our 2018 peer group for the rTSR of our performance unit awards, but otherwise excluded these companies from our 2018 peer group for comparative compensation purposes due to their larger size.

*Joy Global Inc. was included in our 2018 peer group but was removed from our peer group for pay decisions made for 2019, or the 2019 peer group, because it is no longer a public company. Middleby Corporation was added to our 2019 peer group as a replacement.

2018 Compensation Decisions

Base Compensation. We set base salaries for our NEOs generally at a level we deem necessary to attract and retain individuals with superior talent, while taking into account the total compensation package provided to each NEO. Each year we determine base salary adjustments based upon the scope of responsibility and demonstrated proficiency of the executive officers as assessed by the Compensation Committee, and for executive officers other than the CEO, in conjunction with recommendations made by the CEO. No formulaic base salary increases are provided to the NEOs. The Compensation Committee approved base salary increases for Messrs. Coll, Dick and Kirk effective February 1, 2018 and for Messrs. Graziosi and Bohley effective June 1, 2018. Base salaries for our NEOs in 2018 were as follows:

Annual Performance-Based Compensation. Generally, all of our hourly and salaried employees, including our NEOs, are eligible for annual performance-based compensation under the Allison Transmission Holdings, Inc. 2016 Incentive Plan, or the Incentive Plan. We structure our compensation programs to reward employees based on our performance and the individual employee’s relative contribution to that performance. This allows all employees to receive IComp in the event certain specified corporate performance measures are achieved. The annual IComp pool is approved by the Compensation Committee based upon the extent of achievement of corporate-level performance goals established annually by the Compensation Committee.

Payout Potential. Under the terms of the IComp program, the formulaic IComp awards are based upon a percentage of base salary, and target-level performance percentages have been set at or above what our Compensation Committee believes to be market levels, such that our total cash compensation is generally intended to be more performance-based than that of our peers. For our NEOs, this percentage ranged from 100% to 150% of salary for target-level achievement in 2018. Maximum formulaic IComp awards are set at 250% of the target values based on our short-term performance and each NEO’s contributions to that performance. None of our NEOs receives a guaranteed annual IComp award.

The following chart sets forth the formulaic IComp awards for target-level achievement and the maximum formulaic IComp awards for our NEOs for 2018:

Performance Measures. For the year ended December 31, 2018, the Compensation Committee approved the following performance metrics for the IComp program: Adjusted EBITDA as a percent of net sales, Gross adjusted free cash flow and Revenue. The Compensation Committee chose these metrics as they believe that Adjusted EBITDA as a percent of net sales and cash flow metrics are important indicators of our long-term value creation for stockholders. The Revenue metric was included to incent employees to maintain focus on our revenue growth, which is one of our strategic priorities. For this purpose, Adjusted EBITDA as a percent of net sales was defined as earnings before interest expense, income tax expense, amortization of intangible assets, depreciation of property, plant and equipment and other adjustments as defined by our senior secured credit facility divided by net sales, as reported in our Annual Report on Form 10-K for the year ended December 31, 2018, plus, if applicable, adjustments for non-operating activities and/or transactions, such as non-operating legal expenses and/or settlements and capital market transaction costs. No such adjustments for non-operating activities and/or

transactions were made to Adjusted EBITDA as a percent of net sales for purposes of 2018 IComp. For this purpose, Gross adjusted free cash flow was defined as net cash provided by operating activities, less additions of long-lived assets, plus excess tax benefit from stock-based compensation and stockholder activism expenses, as reported in our Annual Report on Form 10-K for the year ended December 31, 2018, plus, if applicable, adjustments for certain transactions related to a change in our U.S. government price reduction reserve, capital expenditures timing decisions versus budget, capital markets transactions, and technology-related initiatives. No such adjustments were made to Adjusted free cash flow for purposes of the Gross adjusted free cash flow metric for 2018 IComp. A reconciliation of Adjusted EBITDA, Adjusted EBITDA as a percent of net sales and Adjusted free cash flow to the most comparable GAAP measures can be found in Part II, Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Non-GAAP Measures” in our Annual Report on Form 10-K for the year ended December 31, 2018, as filed with the SEC on February 26, 2019.

The targets for 2018 IComp were approved by the Compensation Committee in February 2018. Once the extent of achievement of corporate IComp targets and the formulaic IComp calculations have been determined, the Compensation Committee may adjust the total funding amount of IComp awards upward or downward by a maximum of 25% of target IComp based upon its subjective assessment of our overall performance, taking into account the general industry and economic conditions in which we operate, and for IComp awards paid to our NEO group, each NEO’s individual performance, business impact, contributions, leadership and attainment of individual objectives established periodically throughout the year, as well as other related factors. In addition, IComp funding amounts may be adjusted by the Compensation Committee to account for unusual events such as extraordinary transactions, asset dispositions and purchases, mergers and acquisitions, or other factors. The Compensation Committee made no adjustments to the total funding amount for IComp awards for 2018.

The following chart sets forth the weighting of each performance metric, the threshold, target and maximum performance goals, and the actual performance achieved under our IComp program for the year ended December 31, 2018:

Once the extent of achievement of IComp targets has been established, the total IComp funding pool for each metric is interpolated between 50% at threshold to 100% at target and 100% at target to 250% at maximum and then multiplied by the weighting for each performance metric. Based on the foregoing levels of corporate achievement, we exceeded the maximum level of performance for each performance metric, resulting in a payout of 250% of target for 2018 performance.

Applying the 2018 IComp metric performance, formulaic IComp award calculations for the NEOs for the year ended December 31, 2018 were as follows:

The Compensation Committee then further adjusted the formulaic payouts to certain of the NEOs based on the CEO’s recommendations and the Compensation Committee’s subjective assessment of the NEO’s performance, business impact, contributions and leadership, as follows:

The actual IComp awards earned by the NEOs for 2018 are included in the Summary Compensation Table for 2018 under the following columns:

Long-Term Equity Incentive Awards. The Compensation Committee approves annual equity awards, which for the NEOs (other than Messrs. Dewey and Graziosi) in 2018 were in the form of stock options, RSUs and performance units granted under the 2015 Plan at its first regularly scheduled meeting of each year, which typically occurs in February. Specifically, the NEOs’ annual equity awards in 2018 (except for Messrs. Dewey and Graziosi) were allocated as 1/3 of the value in stock options, 1/3 of the value in RSUs and 1/3 of the value in performance units. Mr. Graziosi received a one-time upfront grant of performance units in connection with his promotion to CEO and therefore did not participate in the annual long-term equity program in 2018. The Compensation Committee intends to next consider an equity award for Mr. Graziosi in 2021. Mr. Graziosi’s performance unit award is discussed above under “—2018 CEO and CFO Transition and Related Compensation Decisions.” Mr. Dewey did not receive an annual equity award in 2018 as a result of his pending retirement.

We grant stock options to our NEOs because these awards create value only to the extent our stock price appreciates over the stock price at the time of grant. RSUs were granted because these awards reward executives for stock price appreciation, while providing more stable value to enhance executive retention and limiting incentives for undue risk-taking. Both the 2018 stock option and RSU awards promote executive retention by cliff-vesting three years after the date of grant.

We grant performance units to further emphasize Allison’s long-term market performance and align executives with stockholders. The use of performance units as an equity vehicle is consistent with market best practices for executive pay. For the 2018-2020 performance period, the Compensation Committee approved rTSR as the metric for the performance units granted to Messrs. Bohley, Coll, Dick and Kirk and for 50% of the performance units granted to Mr. Graziosi, with our rTSR compared to the same premier industrial peer group companies that are used to assess competitive pay, plus BorgWarner Inc, Eaton Corporation plc, Cummins Inc. and Parker-Hannifin Corporation, which we believe remain relevant comparators from a performance perspective despite their larger size. The Compensation Committee set a performance target for rTSR at the 50^th percentile of the TSRs of the peer group for the three-year period from January 1, 2018 to December 31, 2020. Possible payouts for the performance units range from: 0% if actual 2018-2020 rTSR is below the 25^th percentile of the TSRs of the peer group, 50% if actual 2018-2020 rTSR is at the 25^th percentile of the TSRs of the peer group, 100% if actual 2018-2020 rTSR is at the 50^th percentile of the TSRs of the peer group and up to 200% if actual 2018-2020 rTSR is at or above the 75^th percentile of the TSRs of the peer group. In addition, the Compensation Committee approved adjusted free cash flow per share as the metric for 50% of the performance units granted to Mr. Graziosi.

For purposes of Mr. Graziosi’s award, adjusted free cash flow per share is calculated as (i) net cash provided by operating activities, less additions of long-lived assets, plus excess tax benefits from stock-based compensation and stockholder activism expenses, plus adjustments for certain transactions related to a change in U.S. government price reduction reserve, capital expenditures timing decisions versus budget, capital markets transactions and technology-based initiatives, as applicable, divided by (ii) the weighted-average number of shares of our common stock outstanding on a fully diluted basis. For Messrs. Bohley, Coll, Dick and Kirk, performance units earned based on 2018-2020 performance will vest no later than February 28, 2021. For Mr. Graziosi, performance units earned based on 2018-2020 performance will vest in equal installments on January 1, 2021, 2022 and 2023, subject to Mr. Graziosi’s continued employment through the applicable vesting date.

For Messrs. Bohley, Coll, Dick and Kirk, the number of stock options, RSUs and performance units granted was determined based on a target dollar value for each executive which was intended to provide a competitive total compensation opportunity relative to market practices, although no specific percentile of market was targeted and the actual value relative to market varies by individual position. For Mr. Graziosi, the annualized value of the front-loaded performance units granted in 2018 was intended to provide a total compensation opportunity at target performance that is consistent with the median of pay for the CEOs among companies in our 2018 peer group. Target values for each of our NEOs except Mr. Dewey for 2018 were as follows:

The target value was then divided by a 60-day average share price to determine the number of shares to grant to our NEOs, and then allocated to stock options, RSUs and performance units, as applicable. The number of shares allocated to stock options was then multiplied by three to reflect the lower value of a stock option as compared to an RSU. Our NEOs, excluding Mr. Dewey, were granted the following awards:

The values of the awards as reported in the Summary Compensation Table are computed in accordance with the Financial Accounting Standards Board’s Accounting Standards Codification Topic 718, or ASC 718. As a result, the equity award values in the Summary Compensation Table differ from the target values described above and used to calibrate the number of shares granted.

Results of the 2016-2018 Performance Units. In 2016, Allison granted performance units that were based on rTSR ranking against a defined comparator group. Performance was measured from January 1, 2016 through the end of December 31, 2018 using a 20-day average share price for the starting and ending dates and including the impact from re-invested dividends. As indicated below, our three-year annualized relative performance of +76% was above the 75^th percentile of the TSRs of the comparator group’s performance of +68%, resulting in a maximum payout of 200% of the target units granted. The Compensation Committee certified this result in February 2019.

Defined Contribution Plans

We maintain a defined contribution plan that is tax-qualified under Section 401(k) of the Internal Revenue Code, or the Code, and that we refer to as the 401(k) Plan. The 401(k) Plan permits eligible salaried employees of the Company to defer receipt of portions of their eligible salaries, subject to certain limitations imposed by the Code, by making contributions to the 401(k) Plan.

We provide matching contributions to the 401(k) Plan in an amount equal to one hundred percent of each participant’s contributions, up to a maximum of four percent of the participant’s annual eligible salary and subject to certain other limits. We make additional contributions to the 401(k) Plan on behalf of certain groups of participants, depending on the date of their commencement of service with our predecessor and whether they are eligible to participate in our defined benefit plan as described below. These contributions are in amounts of either one percent and/or four percent of eligible salary, subject to certain other limits. All matching contributions fully vest after three years of service.

The 401(k) Plan is offered on a nondiscriminatory basis to all our salaried employees, including NEOs, who meet the eligibility requirements. The Compensation Committee believes that matching and other contributions assist us in attracting and retaining talented employees and executives. The 401(k) Plan provides an opportunity for participants to save money for retirement on a tax-qualified basis and to achieve financial security, thereby promoting retention.

Defined Benefit Plans