SCHEDULE 14A

(RULE 14a-101)

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION

PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE

SECURITIES EXCHANGE ACT OF 1934

(AMENDMENT NO. 1)

Filed by the registrant  ☒                         Filed by a Party other than the registrant  ☐

Check the appropriate box:

Aon plc

(Name of Registrant as Specified in Its Charter)

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

Payment of filing fee (Check the appropriate box):

Notice of Annual General

Meeting of Shareholders

Proxy Summary

Voting Matters

Shareholders are being asked to vote on the following matters at the Annual Meeting:

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Certain Proposals Mandated

by English Law

Certain proposals on which you are being asked to vote are customary or required for public limited companies incorporated in England and Wales to present to shareholders at each annual general meeting. These proposals may be unfamiliar to shareholders accustomed to proxy statements for companies organized in other jurisdictions. Specifically, proposals 3, 4, 6, 7, 11, 12, 13, 14 are customary proposals, and may be mandated by English law. Similar proposals were presented to shareholders and approved at prior annual general meetings.

Corporate Governance Highlights

Aon’s commitment to good corporate governance is integral to our business. Highlights of our strong corporate governance practices include:

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Director Nominees

*Independent Director  C = Chair X = Member

1. A = Audit Committee; OC = Organization and Compensation Committee; GN = Governance/Nominating Committee; E = Executive Committee; F = Finance Committee; C = Compliance Sub-Committee

2. Number of other public company boards on which the director sits.

2018 Company Performance Highlights

In 2018, we delivered positive performance across each of our key metrics, highlighted by growth across every major business and record operating margin growth. We continued to execute on our goals of strategically investing in client-serving capability and long-term growth opportunities across our portfolio, managing expenses, and effectively allocating capital to the highest return. Further, we returned approximately $1.8 billion of capital to shareholders through share repurchases and dividends, highlighting our strong cash flow generation and effective allocation of capital.

We believe we are strongly positioned for continued long-term value creation through further improvements in operating performance and strong free cash flow generation coupled with significant financial flexibility.

In assessing our performance, we focus on four metrics that are not recognized under the U.S. generally accepted accounting principles (“GAAP”) that we communicate to shareholders: organic growth, expansion of adjusted operating margins, increase in adjusted diluted earnings per share, and increased free cash flow. These non-GAAP metrics should be viewed in addition to, not instead of, our consolidated financial statements and notes thereto. A reconciliation of these non-GAAP metrics is set forth in Appendix F to this proxy statement.

The following is our measure of 2018 performance against GAAP metrics, as well as the four non-GAAP metrics outlined above:

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2018 Executive

Compensation Highlights

Leadership Performance Program. In early 2019, we settled performance share units granted to our NEOs in 2016 under our eleventh Leadership Performance Program (“LPP”) cycle. The settlement of those units in Class A Ordinary Shares was contingent upon achieving adjusted earnings per share of at least $18.28 (threshold performance) over the performance period from January 1, 2016 to December 31, 2018, and reflects achievement of adjusted earnings per share of $20.31 (after permitted adjustments) which exceeded the target earnings per share of $19.01. Also in 2018, we granted performance share units under the thirteenth cycle of our LPP to each of our NEOs, which are expected to be settled in 2021 contingent upon the Company’s adjusted earnings per share performance over the January 1, 2018 to December 31, 2020 performance period.

Annual Incentive Compensation. Annual incentive bonuses for 2018 were paid to our NEOs in early 2019 following the Company’s achievement of adjusted operating income of $2,464 million, after permitted adjustments. Actual incentive bonuses paid to our NEOs reflected our application of the incentive pool funding guidelines adopted by the Organization and Compensation Committee of the Board (the “Compensation Committee”) (which are based on a comparison of current year adjusted operating income results against the prior year), as well as the Compensation Committee’s evaluation of each NEO’s contributions to our business and financial results, delivery of key strategic initiatives, and personal leadership qualities. Once determined, annual incentives to our NEOs were paid 65% in the form of cash and 35% in the form of time-vested restricted stock units in order to provide value to our executives that is tied to the long-term performance of the Company. The annual incentive awards are described in more detail in the section captioned “Compensation Discussion and Analysis” below.

Compensation-Related Corporate Governance Best Practices

Our compensation philosophy and related governance features are complemented by several policies and practices designed to align our executive compensation program with the long-term interests of our shareholders, including the following:

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Proposal 1–Resolutions Regarding the Re-Election of Directors

The Board of Directors unanimously recommends that shareholders vote

“FOR” each nominee to serve as director.

What am I voting on?

The eleven current members of the Board are standing for re-election, in each case for a one-year term.

The Governance/Nominating Committee of the Board (the “Governance/Nominating Committee”) has recommended to the Board that each director be nominated. With respect to Mr. Case, his employment agreement provides that he will be nominated for election as a director at each annual meeting of shareholders during the period of his employment. All nominees for director have consented to be named and have agreed to serve as directors if re-elected. We have no reason to believe that any of the nominees will not be available to serve as a director. However, if any nominee should become unavailable to serve for any reason, the proxies may be voted for such substitute nominees as may be designated by the Board.

The term of each director expires at the next annual general meeting of shareholders, and each director will continue in office until the election and qualification of his or her respective successor or until his or her earlier death, removal or resignation. Consistent with the terms of the Articles, the Board currently is authorized to have up to twenty-one members and the number of directors was most recently set by the Board at eleven.

Each of the eleven nominees for director will be elected by the vote of a majority of the votes cast with respect to such nominee. A shareholder may: (i) vote for the election of a nominee; (ii) vote against the election of a nominee; or (iii) abstain from voting for a nominee. Unless a proxy contains instructions to the contrary, it is assumed that the proxy will be voted “FOR” the re-election of each nominee named on the following pages. The form of shareholder resolution for this proposal is set forth under the heading “Shareholder Resolutions for 2019 Annual General Meeting” on page 103 of this proxy statement.

Aon values a number of attributes and criteria when identifying nominees to serve as a director, including professional background, expertise, reputation for integrity, business, financial and management experience, leadership capabilities, and diversity. In addition to the specific experience and qualifications set forth below, we believe all of the nominees are individuals with a reputation for integrity, demonstrate strong leadership capabilities, and are able to work collaboratively to make contributions to the Board and management.

Set forth on the following pages is biographical and other background information concerning each nominee for director. This information includes each nominee’s principal occupation as well as a discussion of the specific experience, qualifications, attributes, and skills of each nominee that led to the Board’s conclusion that each nominee should serve as a director. In addition, set forth below is the period during which each nominee has served as a director of Aon, including service as a director of Aon plc’s predecessor, Aon Corporation. The information presented below has been confirmed by each nominee for purposes of its inclusion in this proxy statement.

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Bios

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Corporate Governance

We are committed to continually enhancing our strong corporate governance practices, which we believe help us sustain our success and build long-term value for our shareholders. Aon’s Governance Guidelines provide the framework for our system of corporate governance, which, together with our committee charters and Code of Business Conduct, sets forth standards of conduct for employees, officers, and directors. The Board provides oversight of Aon’s overall performance, strategic direction, and executive management team performance. The Board also approves major initiatives and transactions and advises on key financial and business matters. The Board is kept apprised of the Company’s progress on a regular basis through Board and committee meetings, discussions with management, operating and financial reports provided by our Chief Executive Officer and Chief Financial Officer, and other materials distributed to the Board throughout the year. The charter of each committee, the Governance Guidelines, and the Code of Business Conduct are available on the corporate governance section of our website at http://www.aon.com/about-aon/corporate-governance/corporate-governance.jsp.

Board Leadership Structure

Since 2005, the positions of Chief Executive Officer and Chairman of the Board have been held by separate individuals. Lester B. Knight has served as the Non-Executive Chairman of the Board since 2008. The position of Non-Executive Chairman is independent from management. As Non-Executive Chairman, Mr. Knight sets the agendas for, and presides over, the Board meetings and also chairs executive sessions of the non-management directors. The Chief Executive Officer is also a member of the Board and participates in its meetings. The Board believes the separation of the positions of Chief Executive Officer and Chairman is the appropriate structure at this time as it allows the Chief Executive Officer to focus on the management of the Company and the Chairman to ensure that the Board is focused on its oversight responsibilities, including independent oversight of management.

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Board Role in Risk Oversight

Risk is inherent in every business, and how well a business manages risk can ultimately determine its success. We face a number of risks, including economic risks, competitive risks, financial risks, legal and regulatory risks, cybersecurity risks, and others. Management is responsible for the day-to-day management of risks that we face, while the Board, as a whole and through its committees, has responsibility for the oversight of risk management. In its risk oversight role, the Board has the responsibility to ensure that the risk management processes designed and implemented by management are adequate and functioning as designed.

The Board believes that establishing the right “tone at the top” and full and open communication between management and the Board are essential for effective risk management and oversight. The Board receives presentations from senior management on strategic and risk enterprise matters involving the Company. In addition, senior management attends Board meetings and is available to address any questions or concerns raised by the Board related to risk management and any other matters.

While the Board is ultimately responsible for our risk oversight, the committees of the Board assist the Board in fulfilling its oversight responsibilities in certain areas of risk. The role of each committee in connection with risk oversight is provided in this proxy statement in the section captioned “Board of Directors and Committees.”

The Board believes that its oversight of risks, primarily through delegation of primary responsibility to committees to oversee specific risks within their areas of responsibility and expertise, and the sharing of information with the full Board, is appropriate for a company like Aon. The chair of each committee that oversees risk provides a summary of the matters discussed with the committee to the full Board following each committee meeting. The minutes of each committee meeting are also provided to all Board members.

Director Independence

Aon’s Governance Guidelines require that it have a majority of directors who meet the categorical independence standards adopted by the Board, which must meet or exceed the independence requirements of the NYSE corporate governance standards. The Governance Guidelines further provide that each of the Audit Committee, Governance/Nominating Committee, and Compensation Committee be composed entirely of independent directors.

In connection with the determination of director independence, the Governance/Nominating Committee reviewed the categorical standards together with other applicable legal requirements and the rules of the NYSE. The Governance/Nominating Committee also reviewed information compiled from the responses to questionnaires completed by each nominee for director, information derived from our corporate and financial records, information available from public records, and information received from other relevant parties. Following this review, the Governance/Nominating Committee delivered a report to the Board, and the Board made its determination of director independence.

As a result of this review, the Board affirmatively determined that each nominee for director other than Mr. Case is independent under the categorical standards adopted by the Board, applicable legal requirements, and the rules of the NYSE. Mr. Case is considered a management director because of his position as our Chief Executive Officer.

In determining that each of the non-management directors is independent, the Board also considered the following relationships that it deemed were immaterial to such director’s independence:

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Board of Directors and Committees

The Board met five times in 2018 and acted by unanimous written consent on two occasions. All nominees for director who served as a director in 2018 attended at least 75% (seventy-five percent) of the total meetings of the Board and committees of the Board on which they served.

In accordance with NYSE rules and the Governance Guidelines, non-management directors meet regularly in executive session without management. Mr. Knight chairs these executive sessions.

The Board has established five standing committees: the Executive Committee, the Audit Committee, the Finance Committee, the Governance/Nominating Committee and the Organization and Compensation Committee. The Board has also established the Compliance Sub-Committee as a standing sub-committee of the Audit Committee.

The current membership on each committee is as follows:

Director

Executive Committee

Audit Committee

Compliance Sub- Committee

Finance Committee

Organization and Compensation Committee

Governance/ Nominating Committee

Lester B. Knight

C

C

Gregory C. Case

Jin-Yong Cai

Jeffrey C. Campbell

Fulvio Conti

C

Cheryl A. Francis

J. Michael Losh

C

Richard B. Myers

Richard C. Notebaert

C

Gloria Santona

C

Carolyn Y. Woo

C - Chair

Executive Committee

When the Board is not in session, the Executive Committee is empowered to exercise the power and authority in the management of the business and affairs of Aon as would be exercised by the Board, subject to certain exceptions. The Executive Committee acted by unanimous written consent on four occasions in 2018.

Audit Committee

The primary purposes of the Audit Committee are to assist the Board with the oversight of: (i) the integrity of Aon’s financial statements and financial reporting process; (ii) Aon’s compliance with legal and regulatory requirements and ethics programs established by management and the Board; (iii) the engagement of Aon’s independent auditor, and its qualifications, independence and performance; (iv) subject to the provisions of the Act, the appointment and performance of Aon’s U.K. statutory auditor as required under the Act; and (v) the performance of Aon’s internal audit function. In discharging this role, the Audit Committee is authorized to retain outside counsel or other experts as it deems appropriate to carry out its duties and responsibilities.

The Board has also delegated to the Audit Committee the primary responsibility for the oversight of the Company’s risk management. The charter of the Audit Committee provides that the Audit Committee will discuss guidelines and policies with respect to the Company’s risk assessment and risk management, including the major financial risk exposures facing the Company and the steps management has taken to monitor and control such exposures. The Audit Committee also has primary responsibility for oversight of cybersecurity risk and engages in regular discussion with management regarding

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cybersecurity risk mitigation and incident management. The Audit Committee also has general oversight responsibility for the Company’s legal, regulatory, and ethics policies and programs and annually reviews the adequacy of those policies and programs, including Aon’s Code of Business Conduct. In addition, the Audit Committee periodically reviews with management any material correspondence with, or other action by, regulators or governmental agencies.

In 2018, the Audit Committee met nine times. The Board has determined that each of the members of the Audit Committee is independent as defined by the rules of the NYSE and under the Company’s categorical independence standards, as well as Rule 10A-3 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). In addition, as required by the rules of the NYSE, the Board has determined that all of the Audit Committee members are financially literate, and that Mr. Losh, Mr. Campbell, and Mr. Conti are “audit committee financial experts” within the meaning of rules promulgated by the SEC.

Additional information regarding the Audit Committee’s responsibilities may be found in this proxy statement in the section captioned “Report of the Audit Committee.”

Compliance Sub-Committee

In light of the breadth and number of responsibilities that the Audit Committee must oversee, and the importance of the evaluation and management of risk related to our compliance programs and policies, the Board formed the Compliance Sub-Committee, a standing sub-committee of the Audit Committee. The primary responsibilities of the Compliance Sub-Committee are to: (i) oversee matters of non-financial compliance, including Aon’s implementation of compliance programs, policies, and procedures that are designed to be responsive to the compliance and regulatory risks facing Aon; (ii) assist the Audit Committee in fulfilling its oversight responsibilities for our compliance and ethics programs, policies, and procedures; and (iii) perform any other duties as directed by the Audit Committee or the Board. The Compliance Sub-Committee reports regularly to the Audit Committee and the Board regarding its activities.

Each member of the Compliance Sub-Committee is independent as defined in the independence standards of the NYSE. The Compliance Sub-Committee met four times during 2018.

Finance Committee

The Finance Committee is responsible for assisting the Board with monitoring and overseeing Aon’s balance sheet, including Aon’s capital management strategy, capital structure, investments, returns, and related policies. The Finance Committee also reviews certain proposed mergers, acquisitions, divestitures, and strategic and passive investments in accordance with policies established by the Board. In addition, the Finance Committee oversees the financial, investment, and actuarial policies and objectives of Aon’s U.S. tax-qualified defined benefit plans, reviews the investment performance of non-U.S. benefit and retirement plans, and reviews Aon’s major insurance programs.

Each member of the Finance Committee is independent as defined in the independence standards of the NYSE. The Finance Committee met four times during 2018.

Governance/Nominating Committee

The Governance/Nominating Committee oversees the risks associated with Aon’s overall governance and: (i) identifies and recommends to the Board candidates for service on the Board; (ii) reviews and recommends the re-nomination of incumbent directors for each annual general meeting; (iii) reviews and recommends Board committee appointments; and (iv) leads the annual performance evaluation of the Board and its committees. In addition, the Governance/Nominating Committee develops and recommends the Governance Guidelines to the Board, reviews related party transactions, and annually reviews compliance with share ownership guidelines.

Each member of the Governance/Nominating Committee is independent as defined in the independence standards of the NYSE. The Governance/Nominating Committee met five times during 2018.

Organization and Compensation Committee

The Organization and Compensation Committee assists the Board in carrying out its overall responsibilities with regard to executive compensation, including oversight of the determination and administration of our compensation philosophy, policies, programs, and plans for executive officers and non-management directors. The Compensation Committee annually reviews and determines the compensation of Aon’s executive officers, including the Chief Executive Officer, subject to the input of the independent members of the Board. The Compensation Committee consults with the Chief Executive Officer on, and directly approves, the compensation of other executive officers, including special hiring and severance arrangements.

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The Compensation Committee administers the Amended and Restated Aon plc 2011 Incentive Plan (and its predecessor plans) (the “Shareholder-Approved Plan”), including granting equity (other than awards to the Chief Executive Officer, which awards are approved by the independent members of the Board) and interpreting the Shareholder-Approved Plan, and has certain settlor responsibilities with respect to our other U.S. employee benefit programs. In addition, the Compensation Committee reviews and makes recommendations to the Board concerning non-management director compensation and amendments to U.S. employee benefit plans or equity plans. The Compensation Committee reviews and discusses the compensation disclosures contained in the proxy statement and the U.K. directors’ remuneration report, including the directors’ remuneration policy. As part of these duties, the Compensation Committee reviews the risks associated with Aon’s compensation practices, including an annual review of Aon’s risk assessment of its compensation policies and practices for its employees. The Compensation Committee also reviews and monitors the Company’s policies and practices with respect to diversity, inclusion, and equal employment opportunity.

Each member of the Compensation Committee is independent as defined in the independence standards of the NYSE. The Compensation Committee met eight times during 2018. Additional information regarding the Compensation Committee’s responsibilities may be found in this proxy statement in the sections captioned “Compensation Committee Report” and “Compensation Discussion and Analysis.”

Other Corporate Governance Practices

Director Selection and Shareholder Recommendations

The Governance/Nominating Committee will consider shareholder recommendations for director candidates. Recommendations, together with the name and address of the shareholder making the recommendation, relevant biographical information regarding the proposed candidate, and a description of any arrangement or understanding between the shareholder and the proposed nominee, should be sent to Aon’s Company Secretary. Consistent with the Governance Guidelines, the Governance/Nominating Committee considers a number of criteria in evaluating director candidates, including professional background, expertise, reputation for integrity, business, finance and management experience, leadership capabilities, and potential contributions to the Board. The Governance/Nominating Committee also considers whether a potential nominee would satisfy the categorical independence standards adopted by the Board consistent with the NYSE corporate governance standards.

The Board values diversity as a factor in selecting nominees to serve on the Board and believes that the diversity that exists in its composition provides significant benefits to the Board and Aon. Although there is no specific policy on diversity, the Governance/Nominating Committee considers the criteria noted above in selecting nominees for director in an effort to have a Board comprised of members from diverse backgrounds who have a broad spectrum of experience and expertise and a reputation for integrity. Such considerations may include gender, race, national origin, functional background, executive or professional experience, and international experience. The effectiveness of the nomination process, including the criteria used for selecting nominees for director, is evaluated by the Board each year as part of its annual self-evaluation process and by the Governance/Nominating Committee as it evaluates and identifies director candidates.

When a vacancy exists on the Board due to the expansion of the size of the Board or the resignation or retirement of an existing director, the Governance/Nominating Committee identifies and evaluates potential director nominees. The Governance/Nominating Committee has sole authority to retain and terminate any search firm to be used to identify director candidates and sole authority to approve such search firm’s fees and other retention terms.

Candidates for director are evaluated using the criteria discussed above and the existing composition of the Board, including its size, structure, backgrounds and areas of expertise of existing directors, and the number of independent and management directors. The Governance/Nominating Committee also considers the specific needs of the Board as a whole and the various Board committees. The Governance/Nominating Committee recommends potential director candidates to the full Board, which is responsible for final approval of any director candidate. This process is the same for director candidates who are recommended by our shareholders.

Recommendations for director candidates to stand for election at the 2020 annual general meeting must be submitted in writing to the Company Secretary, Aon plc, The Aon Centre, The Leadenhall Building, 122 Leadenhall Street, London EC3V 4AN, United Kingdom. Recommendations will be forwarded to the Chairman of the Governance/Nominating Committee for review and consideration. For further information, see “Shareholder Proposals for 2020 Annual General Meeting” on page 103 of this proxy statement.

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Communications with the Board of Directors

Shareholders and other interested parties may communicate with the Board by contacting the non-management directors of Aon plc, c/o Office of the Company Secretary, The Aon Centre, The Leadenhall Building, 122 Leadenhall Street, London EC3V 4AN, United Kingdom. Alternatively, shareholders and other interested parties may communicate with Aon’s non-management directors via electronic mail to the following address: corporate.governance@aon.com.

The non-management directors have established procedures for handling communications from shareholders and other interested parties. Communications are distributed to the Chair of the Governance/Nominating Committee, the full Board, the non-management directors, or to any individual director or directors as appropriate, depending on the facts and circumstances outlined in the communication. Solicitations, spam, junk mail and mass mailings, resumes and other forms of job inquiries, business solicitations or advertisements, and frivolous or inappropriate communications will not be forwarded, but will be made available to any non-management director upon request.

Majority Voting

The Articles require that directors be elected by majority vote in uncontested elections. In a contested election, directors will be elected by plurality vote. In addition, the Governance Guidelines provide that any incumbent director who fails to receive a majority of the votes cast in an uncontested election (and who is not otherwise removed by ordinary resolution of the shareholders) must immediately offer to tender his or her resignation to the Board. The Board will then determine, through a process overseen by the Governance/Nominating Committee, whether to accept the resignation, reject the resignation, or take other action. The Board will act on the recommendation of the Governance/Nominating Committee.

Share Ownership Guidelines

The Board has adopted Share Ownership Guidelines for Non-Management Directors and Share Ownership Guidelines for Aon’s senior executives. The Share Ownership Guidelines for Non-Management Directors require each non-management director to hold an investment position in Class A Ordinary Shares equal to five times the annual director retainer and provide a transition period of five years for non-management directors to achieve the requisite ownership level; provided, however, that each new non-management director is expected to hold 1,000 Class A Ordinary Shares within the first year of joining the Board or transitioning from a management director to a non-management director. The guidelines serve to increase our non-management directors’ equity stakes in Aon and align Aon’s non-management directors’ interests more closely with those of Aon’s shareholders. Further information on the Share Ownership Guidelines for Aon’s senior executives can be found in the section captioned “Compensation Discussion and Analysis.”

Hedging and Pledging Shares

The Board has adopted a policy prohibiting all executive officers and directors from engaging in short sales, publicly traded options, puts and calls, forward sale contracts, and other swap, hedging, and derivative transactions relating to our securities. The Board also has adopted a policy prohibiting our executive officers and directors from holding our securities in margin accounts or pledging our securities as collateral for a loan.

Incentive Repayment Policy and Forfeiture Provisions

The Board has adopted an Incentive Repayment Policy applicable to Aon’s executive officers. Pursuant to the Incentive Repayment Policy, the Board may cancel or require reimbursement of any incentive payments or equity-based awards received if the incentive payment or equity award was based on the achievement of financial results that are subsequently restated. If the Board determines that the executive officer engaged in fraud that caused or partially caused the need for the financial restatement, the incentive payment or equity-based award is required to be forfeited or reimbursed in full. If the restatement was not the result of fraud by the executive officer, the Board may, to the extent allowed under applicable law, require forfeiture or reimbursement of the amount the incentive payment or equity-based award exceeded the lower amount that would have been made based on the restated financial results. In addition, beginning with equity-based awards granted in 2019, unvested equity-based awards are subject to forfeiture in the event of a material violation of the Company’s policies or procedures or a breach of applicable restrictive covenants.

Attendance at Annual General Meeting

The Governance Guidelines provide that directors are expected to attend the annual general meeting. All of our Board members then serving, other than Mr. Morrison, attended our 2018 annual general meeting.

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Security Ownership of Directors and

Executive Officers

The following table sets forth the number of Class A Ordinary Shares beneficially owned as of March 15, 2019 by each of the nominees for director, by each of Aon’s NEOs, and by Aon’s directors, nominees and executive officers as a group. As used in this proxy statement, beneficially owned means a person has, or may have within 60 days, the sole or shared power to vote or direct the voting of a security and/or the sole or shared investment power with respect to a security (i.e., the power to dispose or direct the disposition of a security). No shares held by Aon’s directors or executive officers are pledged as security.

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Report of the Audit Committee

The Audit Committee oversees Aon’s financial reporting process on behalf of the Board. Management has the primary responsibility for establishing and maintaining adequate internal financial controls, for preparing the financial statements, and for the reporting process. Ernst & Young US, Aon’s independent registered public accounting firm for 2018, is responsible for expressing opinions on the conformity of Aon’s audited financial statements with generally accepted accounting principles and the effectiveness of Aon’s internal control over financial reporting.

In this context, the Audit Committee reviewed and discussed with management and Ernst & Young US the audited financial statements for the year ended December 31, 2018, as well as management’s assessment of the effectiveness of Aon’s internal control over financial reporting, and Ernst & Young US’s evaluation of Aon’s internal control over financial reporting. The Audit Committee has discussed with Ernst & Young US the matters that are required to be discussed by Auditing Standards and the SEC.

In addition, the Audit Committee has discussed with Ernst & Young US the independence of that firm from Aon and its management, including the matters in the written disclosures required by Rule 3526 of the Public Company Accounting Oversight Board (Communication with Audit Committees Concerning Independence). The Audit Committee has also considered whether Ernst & Young US’s provision of non-audit services to Aon is compatible with maintaining Ernst & Young US’s independence. The Audit Committee has concluded that Ernst & Young US is independent from Aon and its management.

Ernst & Young UK, Aon’s U.K. statutory auditor for 2018, is responsible for expressing opinions on the conformity of Aon’s audited financial statements with the requirements of the Act. The Audit Committee has discussed with Ernst & Young UK the matters that are required to be discussed under the requirements of the Act. The Audit Committee has discussed with Ernst & Young UK the independence of that firm from Aon and its management and the Audit Committee has concluded that Ernst & Young UK is independent.

The Audit Committee discussed with Aon’s internal auditors, Ernst & Young US and Ernst & Young UK, the overall scope and plans for their audits. The Audit Committee meets with the internal and independent auditors, with and without management present, to discuss the results of their examinations, their evaluations of Aon’s internal controls, and the overall quality of Aon’s financial reporting.

In reliance on the reviews and discussions referred to above, and subject to the limitations on the role and responsibilities of the Audit Committee referred to above, the Audit Committee recommended to the Board (and the Board has approved) that the audited financial statements be included in the Annual Report on Form 10-K for the year ended December 31, 2018 for filing with the SEC. The Audit Committee has approved, and the Board has requested that shareholders ratify, the selection of Ernst & Young US as Aon’s independent registered public accounting firm for the year ending December 31, 2019 and Ernst & Young UK as our U.K. statutory auditor (as is also required under the Act) until the next annual general meeting where accounts are laid before the Company.

Auditor Fees

Audit Fees. Fees for audit services totaled approximately $16.6 million for 2018 and $15.9 million in 2017. For both years, audit fees included services associated with the annual audit, including fees related to Section 404 of the Sarbanes Oxley Act of 2002, as amended, the reviews of Aon’s documents filed with the SEC, and substantially all statutory audits required domestically and internationally.

Audit-Related Fees. Fees for audit-related services totaled approximately $1.5 million for 2018 and $1.2 million in 2017. Audit-related fees include services such as employee benefit plan audits, other attestation services, due diligence in connection with acquisitions, and accounting consultations not included in audit fees.

Tax Fees. Fees for tax services, including tax compliance, tax advice and tax planning totaled approximately $3.0 million for 2018 and $1.8 million in 2017.

All Other Fees. Fees for all other services not included above totaled $400,000 for 2018 and $200,000 in 2017. The fees for 2018 and 2017 in this category pertain to permissible services not related to financial reporting.

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Audit Committee’s Pre-Approval Policies and Procedures

The Audit Committee pre-approves all audit and permissible non-audit services provided by the independent registered public accounting firm. These services may include audit services, audit-related services, tax services, and other services. Each pre-approval provides details regarding the particular service or category of service to be provided. The Audit Committee requires that the independent registered public accounting firm and management report on the actual fees charged by the independent registered public accounting firm for each category of service at Audit Committee meetings held during the year.

The Audit Committee may pre-approve engagements either on a case-by-case basis or on a category basis. The Audit Committee grants pre-approvals for certain categories of services at the start of each year which are applicable for the year. In considering these pre-approvals, the Audit Committee reviews a description of the scope of services falling within each category and approves budgetary limits for each category. The Audit Committee acknowledges that circumstances may arise throughout the year that require the engagement of the independent registered public accounting firm to provide additional services not contemplated in the Audit Committee’s initial pre-approval process. In those circumstances, the Audit Committee requires that specific pre-approval be obtained for any audit or permitted non-audit service that is not included in an approved category, or for which total fees are expected to exceed the relevant budgetary limits. The Audit Committee also requires specific pre-approval be obtained for any services in the other services category.

The Audit Committee has delegated pre-approval authority to the Chairman of the Audit Committee for those instances when pre-approval is needed prior to a scheduled Audit Committee meeting. Such pre-approvals are reported to the Audit Committee at the next scheduled Audit Committee meeting.

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Principal Holders of Voting Securities

As of March 15, 2019, the beneficial owners of 5% or more of Aon’s Class A Ordinary Shares entitled to vote at the Annual Meeting and known to the Company were:

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Proposal 2–Advisory Resolution on Executive Compensation

The Board of Directors unanimously recommends that shareholders vote “FOR” advisory approval of the compensation of Aon’s NEOs.

What am I voting on?

In accordance with applicable law and Section 14A of the Exchange Act, we are providing shareholders with the opportunity to vote on an advisory resolution, commonly known as “say on pay,” approving Aon’s executive compensation as reported in this proxy statement.

At our 2018 annual general meeting, we provided shareholders with the opportunity to vote on an advisory resolution regarding the executive compensation of our NEOs as disclosed in the proxy statement for the 2018 annual general meeting, and shareholders approved the proposal by a large majority.

We encourage shareholders to read the Compensation Discussion and Analysis beginning on page 25 of this proxy statement, which describes in detail how our compensation policies and procedures operate and are designed to achieve our compensation objectives of (1) directly linking the compensation of our NEOs to our performance, and (2) aligning the financial interests of our NEOs with those of our shareholders, as well as the Summary Compensation Table for Fiscal Years 2018, 2017, and 2016, and other related tabular and narrative disclosures beginning on page 39 of this proxy statement, which provide detailed information on the compensation of our NEOs.

The Board and the Compensation Committee believe that the policies and procedures articulated in the Compensation Discussion and Analysis are effective in achieving our compensation objectives, and that the design of our compensation program and the compensation awarded to our NEOs fulfill these objectives.

The form of shareholder resolution for this proposal is set forth under the heading “Shareholder Resolutions for 2019 Annual General Meeting” on page 95 of this proxy statement.

Is this vote binding on the Board?

As this vote is advisory, it will not be binding upon the Board or the Compensation Committee, and neither the Board nor the Compensation Committee will be required to take any action (or refrain from taking any action) as a result of the outcome of the vote on this proposal. The Compensation Committee will review and consider the outcome of the vote in connection with the ongoing review of Aon’s executive compensation programs.

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Compensation Committee Report

The Organization and Compensation Committee of the Board of Aon has reviewed and discussed with management the Compensation Discussion and Analysis required by Item 402(b) of Regulation S-K and set forth in this proxy statement.

Based on its review and discussions with management, the Organization and Compensation Committee recommended to the Board that the Compensation Discussion and Analysis be included in this proxy statement and incorporated into Aon’s Annual Report on Form 10-K.

This Report is provided by the Organization and Compensation Committee, which is composed entirely of the following independent directors:

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Compensation Discussion and Analysis

This Compensation Discussion and Analysis (“CD&A”) describes our executive compensation program for our NEOs for 2018, who are listed below. We recommend that you read this section in conjunction with the executive compensation tables and corresponding footnotes that follow, as it provides context for the amounts shown in the tables and the footnote disclosures.

Executive Summary

Who We Are    

Aon is a leading global professional services firm providing a broad range of risk, retirement and health solutions. Our approximately 50,000 colleagues in 120 countries empower results for clients by using proprietary data and analytics to deliver insights that reduce volatility and improve performance.

2018 Business Highlights

In assessing our performance, we focus on four non-GAAP metrics that we communicate to shareholders: organic growth, expansion of adjusted operating margins, increase in adjusted diluted earnings per share, and increased free cash flow. These non-GAAP metrics should be viewed in addition to, not instead of, our consolidated financial statements and notes thereto. A reconciliation of these non-GAAP metrics is set forth in Appendix D to this proxy statement.

In 2018, we continued to deliver against these four metrics:

Performing to these metrics allows us to continue to execute on our goals of strategically investing in long-term growth, improving return on invested capital, and effectively allocating capital.

During 2018, we returned approximately $1.8 billion in excess capital to our shareholders, including $1.4 billion in share repurchases and $400 million in dividends, which highlights our strong cash flow generation and effective allocation of capital. During Mr. Case’s leadership, which began in April 2005, our average annual total shareholder return has been 16%, compared to the return of the benchmark S&P 500 of 6% and 9% for our direct peer averages (Arthur J. Gallagher & Co., Brown & Brown, Inc., Marsh & McLennan Companies, Inc. and Willis Towers Watson Public Limited Company). We believe we are well positioned to create long-term value by improving our operating performance and generating strong free cash flow.

We compensate our senior executives through incentive programs that measure both long-term and short-term performance. Our long-term incentive program (described in detail under “Leadership Performance Program Under Our 2011 Incentive Plan”) is based on adjusted cumulative earnings per share (a measure driven by operational performance and capital management) across overlapping three-year performance periods. Our short-term incentive program (described in detail under “Annual Incentive Awards Under Our Shareholder-Approved Plan”) is based on adjusted operating income, a measure driven by operating margin and organic revenue growth.

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We achieved strong results against these two metrics, which were the key performance measures under our 2018 annual and 2016-2018 long-term incentive compensation programs. Set forth below are the results against these metrics as well as the results against their GAAP comparative metrics:

Because our short-range or long-range corporate planning may dictate a change to the metrics we use over time, we expect to continue reassessing the metrics annually.

Features of Our Executive Compensation Program

The following table provides an overview of our compensation program elements for our NEOs. The guiding philosophy underlying our executive compensation program is to provide a fair, flexible, and market-based total compensation package that is heavily tied to the Company’s short- and long-term performance and aligned with the interests of our shareholders.

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Our Pay For Performance Orientation and Executive Compensation Philosophy

The core principle of our executive compensation program continues to be pay for performance, as we continue towards our goal of being the leading global professional services firm focused on risk, health, and retirement. That core principle dictates that performance-based pay elements (which constitute the bulk of our NEOs’ total direct compensation) will not be earned or paid unless our shareholders benefit first. In respect of 2018, performance-based compensation comprised approximately 90% of the total direct compensation for Mr. Case and approximately 81% of the total direct compensation on average for our other NEOs:

2018 Total Direct Compensation-CEO 2018 Total Direct Compensation-All Other NEOs

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The “performance-based” pay component of the above graphs is the sum of (1) the cash portion of the NEO’s bonus paid for 2018 performance, plus (2) the target value of all performance-based equity awards granted to the NEO for 2018 performance or during 2018. The “fixed” pay component is the NEO’s 2018 base salary. For our NEOs other than Mr. Case, the actual performance-based amount of total direct compensation ranged from 77% to 86%. Please refer to the Summary Compensation Table below for complete disclosure of the total compensation paid to our NEOs serving in that capacity during the prior three years.

In addition to our heavy focus on pay for performance, our compensation program is complemented by several practices designed to align our executive compensation program with the long-term interests of our shareholders:

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2018 Executive Compensation Highlights

Leadership Performance Program. In early 2019, we settled performance share units granted to our NEOs in 2016 under our eleventh LPP cycle (“LPP 11”). The settlement of those units in Class A Ordinary Shares was contingent upon achieving adjusted earnings per share of at least $18.28 (threshold performance) over the performance period from January 1, 2016 to December 31, 2018, and reflects achievement of adjusted earnings per share of $20.31 (after permitted adjustments), which exceeded the target earnings per share of $19.01. Also in 2018, we granted performance share units under our thirteenth LPP cycle (“LPP 13”) to each of our NEOs, which are expected to be settled in 2021 contingent upon the Company’s adjusted earnings per share performance over the January 1, 2018 to December 31, 2020 performance period.

Annual Incentive Compensation. Annual incentive bonuses for 2018 were paid to our NEOs in early 2019 following the Company’s achievement of adjusted operating income of $2,697 million (after permitted adjustments), compared to a pre-determined minimum achievement threshold of $1,635 million. Actual incentive bonuses paid to our NEOs reflected our application of the incentive pool funding guidelines adopted by the Compensation Committee (which are based on a comparison of current year adjusted operating income results against the prior year), as well as the Compensation Committee’s evaluation of each NEO’s contributions to our business and financial results, delivery of key strategic initiatives, and personal leadership qualities. Once determined, annual incentives to our NEOs were paid 65% in the form of cash and 35% in the form of time-vested restricted share units in order to provide value to our executives that is tied to the long-term performance of the Company.

The Executive Compensation Process

Process of Determining Executive Compensation

Management assists the Compensation Committee in managing our executive and director compensation programs. Direct responsibilities of management include, but are not limited to:

In the first quarter of 2018, our independent directors evaluated our Chief Executive Officer’s performance and compensation. At that time, the Compensation Committee also evaluated the performance and reviewed the compensation of selected other senior executives. During this review, the Compensation Committee approved for each executive officer a target annual incentive for 2018 performance and the specific corporate performance metric that our performance would be measured against for 2018.

In early 2019, and in connection with the Compensation Committee’s annual compensation review, management presented the Compensation Committee with compensation tally sheets reporting compensation paid for the prior four years and competitive pay data, where available, as a market check. The Compensation Committee also reviewed and considered Aon’s overall performance against targets that were established for 2018. This review culminated in certain compensation decisions made by the Compensation Committee with respect to our executive officers during the first quarter of 2019, which are described in more detail below.

Relationship With Executive Compensation Consultant

Since 2005, the Compensation Committee has retained Frederic W. Cook & Co., Inc. (“FW Cook”) as its independent compensation consultant. FW Cook provides expertise on various matters coming before the Compensation Committee. FW Cook is engaged by, and reports directly to, the Compensation Committee, and does not advise management or receive other compensation from Aon. FW Cook typically participates in all Compensation Committee meetings during which executive compensation matters are discussed and communicates with the Chair of the Compensation Committee between meetings. During 2018, FW Cook assisted the Compensation Committee by providing insights and advice regarding our

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compensation philosophy, objectives, and strategy; developing criteria for identification of our peer group for executive and Board compensation and Company performance review purposes; reviewing management’s design proposals for short-term cash and long-term equity incentive compensation programs; providing insights and advice regarding our analysis of risks arising from our compensation policies and practices; providing change in control severance calculations for our NEOs in the 2018 annual proxy disclosure; providing compensation data from our peer group proxy and other disclosures; advising on the terms and conditions of the renewal of employment agreements and transition to employment letters with our senior executive officers; and advising and providing comments on management’s recommendations regarding executive officers’ annual incentives for 2018 and equity-based awards granted in 2018. Management periodically retains other consulting firms to provide pay survey data and other non-executive compensation services that may be presented to or reviewed by the Compensation Committee.

The Compensation Committee has assessed the independence of FW Cook pursuant to SEC and NYSE rules and concluded that no conflict of interest exists that would prevent FW Cook from serving as an independent consultant to the Compensation Committee.

How We Determine Total Compensation

The Compensation Committee generally targets a competitive level and mix of total direct compensation elements using market data as a reference point. For 2018, the Compensation Committee did not use a specific formula or any specific benchmark or target to determine total compensation, individual components of compensation, or the relative mix of pay components, and setting compensation levels in 2018 was not a mechanical process. Rather, the Compensation Committee used its judgment and business experience. The Compensation Committee’s overall intent was to manage the various elements of total compensation together so that the emphasis of the Company’s compensation program was on its variable components of pay, including long-term equity awards and annual bonus awards that fluctuate based on Aon’s performance.

Use of Tally Sheets

The Compensation Committee regularly reviews compensation tally sheets. The tally sheets assign dollar amounts to each component of the executive’s compensation, including base salary, annual incentives (target and actual), long-term incentives granted and outstanding, and employee benefits (including health care and qualified and non-qualified retirement plans), relocation benefits including income tax equalization, perquisites, and potential change in control severance payments. The tally sheets are presented to the Compensation Committee to ensure it is aware of all rewards components and the value of such elements when making compensation decisions.

Involvement of Mr. Case in the Compensation Process

Each year, the Compensation Committee approves all elements of compensation for our NEOs and other executive officers (other than Mr. Case). These decisions are typically made during the annual compensation review process conducted in the first quarter of the year. The Compensation Committee solicits certain recommendations from Mr. Case and our Chief Human Resources Officer.

Mr. Case recommends to the Compensation Committee the equity award, annual incentive payment, and base salary adjustments, if any, for the executive officers who report directly to him. He has direct knowledge of the contributions made to Aon by those executive officers and he shares this knowledge with the Compensation Committee. Mr. Case supports his recommendations by providing performance evaluations for his direct reports.

During the annual review process, our Chief Human Resources Officer and the Chairman of the Compensation Committee work together on Mr. Case’s annual evaluation report, which summarizes Mr. Case’s qualitative and quantitative performance. The report is considered, along with other factors (including the Compensation Committee’s own assessment of Mr. Case’s performance, relevant market data, and Aon’s overall performance), in determining Mr. Case’s compensation.

The Compensation Committee has the ultimate authority to make compensation decisions. The Compensation Committee discusses its preliminary compensation decisions with the independent members of the Board who do not serve on the Compensation Committee. This process garners valuable input from those directors regarding the executives’ performance. The sharing of performance review information also aids the directors in carrying out their succession planning responsibilities. After considering input from those directors, the Compensation Committee makes its final determination.

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Mr. Case, together with our Chief Human Resources Officer and our Chief Financial Officer, makes recommendations to the Compensation Committee relating to the corporate performance targets to be established under Aon’s annual incentive and long-term equity incentive programs. The Compensation Committee reviews such recommendations with FW Cook and reserves the ultimate authority to set such targets and to determine whether such goals were achieved.

Result of Advisory Vote by Shareholders on Our “Say on Pay” Proposal

The Compensation Committee considered the results of the advisory vote by shareholders on the “say on pay” proposal presented to our shareholders at our 2018 annual general meeting of shareholders. As reported in our Current Report on Form 8-K, filed with the SEC on June 27, 2018, approximately 83% of shareholder votes cast at that meeting were voted in support of the compensation program offered to our NEOs. Accordingly, the Compensation Committee made no changes to our executive compensation programs as a result of such vote.

Review of Compensation Policies and Practices

We believe that we maintain an appropriate level of prudence associated with our compensation programs and will continue to do so. We engage in a process to evaluate whether our executive and broad-based compensation programs contribute to unnecessary risk-taking, which includes an assessment by the Compensation Committee’s independent consultant of whether these programs create material risk. We have concluded that the risks arising from these programs are not reasonably likely to have a material adverse effect on the Company. In the first quarter of 2019, FW Cook assessed our executive compensation policies and practices and also concluded that they do not motivate imprudent risk-taking.

Internal Pay Relationships

In determining an executive officer’s target annual incentive or long-term performance award value, the Compensation Committee will, from time to time, consider internal pay relationships. However, the Compensation Committee has not adopted a broad internal pay equity policy pursuant to which each executive officer’s compensation, or one or more components thereof, is related to or benchmarked against the compensation of other executive officers.

Tax Deductibility of Executive Compensation

Prior to the passage of the Tax Cuts and Jobs Act of 2017 (the “TCJA”) on December 22, 2017, Section 162(m) of the Internal Revenue Code of 1986, as amended (the “Code”), generally disallowed a tax deduction to publicly held companies for compensation paid to certain covered executive officers in excess of $1 million per officer, unless such compensation qualified as “performance-based.” Under the TCJA, the performance-based exception has been repealed with respect to taxable years beginning after December 31, 2017; however, the new rules do not apply to compensation paid pursuant to a written binding contract in effect as of November 2, 2017 that is not materially modified thereafter. While the TCJA may limit the deductibility of compensation paid to our NEOs, the Compensation Committee will continue to monitor developments in this area and will—consistent with past practice—retain flexibility to design compensation programs that are in the best long-term interests of the Company and our shareholders.

Compensation Committee Interlocks and Insider Participation

During 2018, the Compensation Committee was composed of Mr. Notebaert (Chairman), Mr. Cai, Mr. Campbell, Ms. Francis, Mr. Morrison (until his resignation from the Board on June 22, 2018), General Myers, and Dr. Woo. No member of the Compensation Committee was, during 2018 or previously, an officer or employee of Aon or any of its subsidiaries. In addition, during 2018, there were no Compensation Committee interlocks required to be disclosed.

Analysis of Key 2018 Compensation Decisions

Peer Group

Our peer group is reviewed on an annual basis. We set executive compensation at levels that we believe are appropriate and competitive for global professional services firms within our market sector and the general industry marketplace. We review annual financial reports filed by our peer group. For purposes of evaluating the competitive market (but not for purposes of benchmarking to specific percentiles), we look at peer group compensation data. We compare the total direct compensation (defined as base salary, actual bonus, and equity-based awards) for our NEOs to the total direct compensation for executives at selected peer companies where job descriptions are sufficiently similar to those of our executives to permit comparison.

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In November 2017, we reviewed our peer group composition with FW Cook. The defined criteria used to establish our peer group includes global financial services industry companies or major consulting firms with which we compete for executive talent or financial capital, that are between one-third and three times our size in average market capitalization (calculated over the most recent eight quarters to reduce volatility), between one-fourth and four times our size in trailing four-quarter revenues, and with at least half our headcount or revenues per employee that are between one-half and two times our revenues per employee. As a result of the peer group composition review, we determined that three companies (Aetna Inc., Automatic Data Processing, Inc., and Xerox Corporation) should be removed as they longer fell within the defined criteria used to establish our peer group due to financial metrics or type of business, and two new companies (Fidelity National Information Services and Morgan Stanley) should be added to better represent the information technology services and diversified financial GICS classification. In addition, the peer group was adjusted to reflect the entity name changes of Computer Sciences Corporation and McGraw Hill Financial, Co., to DXC Technology and S&P Global, Inc., respectively. The Compensation Committee referred to this 2018 peer group when determining the actual annual incentive award paid in 2018 related to 2017 performance.

In November 2018, we again reviewed our peer group composition with FW Cook. As a result of that review, we determined that no changes to our peer group were warranted. The Compensation Committee referred to the 2019 peer group when determining the actual annual incentive awards paid in 2019 related to 2018 performance. Our 2018 and 2019 peer group members are listed below:

Base Salary

Using the peer group and executive compensation review processes outlined above, the Compensation Committee annually considers and reviews salaries for our executive officers. While base salaries for our senior executives are adjusted infrequently, they may be occasionally adjusted to, among other things, recognize changes in job responsibilities or to bring the fixed component of an executive’s total compensation in line with his or her peers at the Company or the industry generally. Where approved, base salary adjustments generally take effect on April 1. The base salaries for our NEOs were not adjusted in 2018.

Leadership Performance Program Under Our Shareholder-Approved Plan

During the first quarter of 2018, we granted performance share units to our executive officers, including each NEO, pursuant to LPP 13, a sub-plan of our Shareholder-Approved Plan. During the first quarter of 2019, we determined our actual levels of achievement under LPP 11.

LPP 13. This is our thirteenth layer of consecutive three-year performance cycles for long-term incentive awards granted to our most senior leaders. It is intended to further strengthen the relationship between capital accumulation for our executives and long-term financial performance of the Company and increasing shareholder value. The performance share units awarded under LPP 13 are payable (to the extent earned) in the form of Class A Ordinary Shares. The nominal value of the awards was determined and approved by the Compensation Committee. The number of target performance share units was calculated on the date of grant based on that day’s closing price for Class A Ordinary Shares on the NYSE. The performance share units under LPP 13 will be earned and settled in a range of 0% (if the threshold level is not achieved) to 200% of the target number of shares based on the Company’s cumulative adjusted EPS over the three-year performance period.

The performance results for LPP 13 will be measured against three-year publicly reported adjusted cumulative EPS growth rate, subject to limited adjustments set forth in the program documentation at the beginning of the three-year period. The adjustments are intended to exclude the impact of unusual or infrequently occurring items, so as to provide a target that, while challenging, eliminates the impact of certain events and circumstances outside of the control of the relevant executive

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officers. The Compensation Committee’s selection under LPP 13 of the three-year performance period and cumulative adjusted EPS financial performance metric provides the award recipients a reasonable period of time within which to achieve and sustain challenging long-term growth objectives. The Compensation Committee believes adjusted EPS is a more effective measure of Company performance for purposes of motivating executive performance than against EPS calculated in accordance with U.S. GAAP, as the adjusted measure provides a target that is within the executives’ control and area of accountability. Further, the Company believes that adjusted EPS provides a perspective on the Company’s ongoing core operating performance that is more consistent with how shareholders measure our success and that creates transparency and clarity for participants.

In determining the individual awards under LPP 13, the Compensation Committee considered internal pay relationships, the award recipient’s compensation mix, and total direct compensation.

LPP 11. In early 2019, we determined the actual achievement under LPP 11. The performance period for LPP 11 ended on December 31, 2018.

LPP 11—Performance Share Units (Performance Period 1/1/2016—12/31/2018)

For LPP 11, the cumulative adjusted EPS goals from continuing operations ranged from a threshold level of $18.28, below which no payout would occur, to $20.72 or higher, which would have yielded shares equal to 200% of the target number. A result of $19.01 in cumulative adjusted EPS from continuing operations would have yielded shares equal to 100% of the target number. This target represented a 4.8% increase over the EPS target for the tenth cycle of our LPP established for the performance period from 2015 through 2017 (“LPP 10”). Our actual cumulative adjusted EPS from continuing operations for the three-year period (after permitted adjustments, as described below) was $20.31, resulting in a payout at 183% of target.

The adjusted EPS from continuing operations results for LPP 11 include adjustments detailed by the plan governing LPP 11 and approved by the Compensation Committee. For each year of the performance period associated with LPP 11, adjustments to EPS from continuing operations were approved by the Compensation Committee to address the impact of extraordinary legal settlements, the divestiture of our benefits administration and business process outsourcing platform, the disposition of National Flood Services, and restructuring savings. Each NEO received a distribution under LPP 11.

We do not pay dividends or dividend equivalents on performance share units.

Annual Incentive Awards Under Our 2011 Incentive Plan

Shareholder-Approved Plan. Under our Shareholder-Approved Plan, the Compensation Committee annually approves the framework for our annual incentive compensation program, including the applicable Aon-wide performance metric and minimum achievement threshold against that performance metric. If the metric is not achieved, no annual bonuses are payable under the Shareholder-Approved Plan. If the minimum achievement threshold is met, the Shareholder-Approved Plan allows for the payment of current-year annual incentives to our executive officers up to a cap of the lesser of $10 million or the maximum annual incentive otherwise established by the Compensation Committee for each executive officer. For 2018, the Compensation Committee established a cap of 300% of each NEO’s target annual incentive.

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In the first quarter of 2018, the Compensation Committee set annual incentive eligibility for our NEOs. For each NEO, annual incentive eligibility was set as a target percentage of the executive’s base salary at year end (and, for Ms. Davies and Mr. Lieb, their annual foreign service allowance received in connection with their relocation to London). The target annual incentives for each of our NEOs are shown in the table below:

The Shareholder-Approved Plan does not provide guidelines or formulas for determining the actual annual incentives payable to our executive officers once the metric is achieved. If the metric is achieved, the Shareholder-Approved Plan allows the Compensation Committee to award an annual incentive up to the previously established cap. As explained below, for 2018, the Compensation Committee adopted a framework (the “Executive Committee Incentive Compensation Plan”) for determining actual annual incentives to be paid if the metric under the Shareholder-Approved Plan was achieved.

2018 Metric Under Shareholder-Approved Plan. In the first quarter of 2018, the Compensation Committee determined that 2018 Aon-wide performance would be measured by growth in adjusted operating income (“OI”) for 2018 (as adjusted for unusual or infrequently occurring items) as compared to a 2017 baseline adjusted OI number of $2,277 million. The 2017 baseline was determined based on 2017 adjusted OI ($2,336 million) less $59 million related to the restatement of OI due to the adoption of the Financial Accounting Standard Board’s new revenue recognition standard, effective January 1, 2018. The Compensation Committee set the minimum achievement threshold at 70% of the 2017 adjusted OI, or $1,635 million. The Compensation Committee retained the discretion to further adjust OI under the plan for extraordinary, unusual, or infrequently occurring items. The Compensation Committee selected OI as the measure to emphasize performance of Aon as a whole and directly link executives’ awards to Aon’s key business initiatives of delivering distinctive client value and achieving operational excellence.

The Compensation Committee set the minimum threshold at 70% because we believed performance below that level would not create sufficient value for the Company’s shareholders and, therefore, should not result in annual incentive payments. If the minimum achievement threshold is satisfied, an annual incentive pool is funded as described below under “Determining 2018 Annual Incentives.”

2018 Actual Performance. During the first quarter of 2019, the Compensation Committee determined that Aon’s 2018 adjusted OI was $2,464 million (after permitted adjustments), or 108.2%, of the 2017 baseline. This exceeded the minimum threshold established under the Shareholder-Approved Plan.

Determining 2018 Annual Incentives. In the first quarter of 2018, the Compensation Committee approved the Executive Committee Incentive Compensation Plan for funding the total annual incentive pool under the Shareholder-Approved Plan for those executives and members of senior management that at such time comprised Aon’s management executive committee. That group included each of our NEOs. The rationale for establishing this funding framework was to provide executives with a clear connection between the expected reward and the required performance, as well as a basis for annual incentive accruals. Under those guidelines, the size of the incentive pool generally equals the budgeted accruals for aggregate target annual incentive payments for members of the Company’s executive committee, multiplied by the percentage increase in OI from the 2017 baseline to 2018 (reduced by 200 basis points), although the Compensation Committee retains the discretion to approve increases (up to 10%) and decreases (up to 20%) in the size of the incentive pool. In other words, the incentive pool is only funded at target if there is a 2% increase in adjusted OI over the previous year. However, no individual could receive an award in excess of the maximum amount established by the Committee (the lesser of $10 million or three times their target annual incentive).

In accordance with the Shareholder-Approved Plan, the Executive Committee Incentive Compensation Plan would not be funded unless Aon achieved the minimum threshold of 70% of the 2017 baseline. After determining that the minimum

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threshold had been achieved, the Compensation Committee then met in February 2019 to determine the funding status of the incentive pool. After application of the formula guidelines described above, the total incentive pool reserved for members of the Company’s executive committee (including our NEOs), was determined to be $15.5 million. None of the NEOs received their maximum annual incentive of the lesser of $10 million or three times their target annual incentive. Each NEO received in the range of 100% to 111% of their target annual incentive, other than Mr. Case, who received an annual incentive of $2 million, or 67% of target annual incentive. For Mr. Case, the Board decided to reallocate the mix of short-term and long-term incentives by shifting $1 million of short-term incentives related to 2018 (payable in 2019) to a $1 million increase in Mr. Case’s long-term LPP award that vests in 2022, and is contingent upon obtaining longer-term 3-year performance goals.

The following table sets forth the actual annual incentive paid to each of our NEOs under the Executive Committee Incentive Compensation Plan for the year:

In determining annual incentives for our NEOs, the Compensation Committee (or, with respect to Mr. Case, the independent members of the Board) took into account several factors, including Mr. Case’s compensation recommendations for the NEOs (other than himself), business and financial results, individual delivery of key strategic initiatives, and personal leadership qualities.

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Generally, all annual incentive awards for executive officers are payable 65% in cash and 35% in restricted share units, with such restricted share units vesting ratably over a three-year period (subject to certain forfeiture provisions). These restricted share units are intended to further focus employees’ attention on Aon’s long-term performance and to further promote retention and increased share ownership. These awards will be settled (to the extent vested) in Class A Ordinary Shares; we also provide dividend equivalents on unvested restricted share units in cash at the same time that actual dividends are paid. The Compensation Committee believes that paying a substantial portion of the executive’s annual incentive award in the form of restricted share units strikes a fair balance between reward for past performance and incentive for future improvements. The restricted share units and the cash portion of the bonus were paid to executives during the first quarter of 2019 for 2018 performance.

Executive and Relocation Benefits

Executive Benefits. In addition to our broad-based employee benefit programs that are available to our employees generally (such as health coverage, 401(k) plan, etc.), each of our currently serving NEOs is eligible to participate in a deferred compensation program and a supplemental savings plan. Only Mr. Andersen participates in our defined benefit pension plan or the supplemental pension program because each other NEO was hired after the Aon Pension Plan was closed to new hires in 2004. Additional information regarding these qualified and non-qualified plan benefits is set forth under the headings “Pension Benefits in Fiscal 2018” and “Nonqualified Deferred Compensation in Fiscal 2018” contained in this proxy statement. We also provide an executive health screening program available to all members of our management executive committee, including our NEOs.

Relocation Benefits. In 2018, we continued to provide relocation benefits resulting from our relocation of our headquarters to London, United Kingdom to certain of our NEOs. Relocation benefits are customary for expatriate assignments for us and other employers in our industry. The Compensation Committee approved certain relocation benefits for the relocating executives after consulting with FW Cook, and each relocating executive has signed an international assignment letter with Aon that sets forth the relocation benefits available to him or her. The relocation packages for our NEOs are intended to keep them “whole” on a total rewards basis, be transparent and equitable, and reflect competitive practices and benchmarks of industry peers. The Compensation Committee periodically reviews the relocation packages of our executives. These benefits are provided pursuant to international assignment letters with our NEOs on assignment, which are described in more detail under the heading “International Assignment Letters.”

The compensation received in the form of such benefits is reflected in the Summary Compensation Table for Fiscal Years 2018, 2017, and 2016.

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Post-Termination Compensation

We believe that providing severance and change in control severance benefits is critical to recruit talented employees and secure the continued employment and dedication of our existing employees. All or nearly all of the companies with which we compete for talent have similar arrangements in place for their senior executives. While we consider these benefits to be necessary, the terms of these benefits are not considered as part of the compensation strategy when the Compensation Committee annually determines the compensation for the NEOs. Additional information about post-termination compensation is set forth in the section captioned “Potential Payments on Termination or Change-in-Control” contained in this proxy statement.

Severance Benefits Upon Change in Control. Our NEOs, other than Mr. Case, are eligible for change in control severance benefits under our Combined Severance Plan. The Combined Severance Plan provides that covered executives would receive certain severance benefits upon qualifying terminations of employment in connection with or within two years following a change in control of Aon. Thus, the Combined Severance Plan requires a “double trigger”—a qualifying change in control of Aon and a qualifying termination of the executive’s employment—for severance benefits to become payable. Mr. Case, who is not covered under the Combined Severance Plan, is party to an individual change in control severance agreement with the Company that also provides certain severance benefits upon a qualifying termination in connection with or within two years following a change in control of Aon. Neither the Combined Severance Plan nor Mr. Case’s individual agreement provides for excise tax gross-up protection in the event the executive becomes subject to tax under Section 280G of the Code in connection with such double trigger.

Additional information regarding the change in control arrangements for our NEOs is set forth in the section captioned “Potential Payments on Termination or Change in Control” contained in this proxy statement.

Severance Benefits Pursuant to Employment Agreements and Combined Severance Plan. We have entered into agreements with certain executive officers that provide for post-employment severance benefits and transitional compensation if the officer’s employment terminates for a qualifying event or circumstance unrelated to a change in control of Aon, such as being terminated without “cause” as such term is defined in the operative agreement. To the extent that members of our executive committee (including our NEOs) are not party to an individual employment agreement providing for severance benefits, those individuals are eligible to receive severance benefits under the Combined Severance Plan. During 2018, each of our NEOs had an employment agreement providing for severance benefits or were eligible to receive severance benefits under the Combined Severance Plan. Additional information regarding such post-employment severance or transitional compensation for Mr. Case and the other NEOs is set forth in the section captioned “Potential Payments on Termination or Change in Control” contained in this proxy statement.

Directors’ Remuneration Policy

In accordance with English law, our shareholders approved our directors’ remuneration policy at our 2017 annual general meeting. The directors’ remuneration policy is consistent with the compensation programs and policies set forth in this CD&A and provides a binding framework within which the Compensation Committee oversees the Company’s compensation programs applicable to management and non-management directors. The directors’ remuneration policy provides the Compensation Committee with discretion to administer the Company’s compensation programs.

As reported in our Current Report on Form 8-K filed with the SEC on June 27, 2017, there was significant support by shareholders for the directors’ remuneration policy. All compensation reported in this proxy statement was in compliance with the approved directors’ remuneration policy.

Extensions of Employment Arrangements for Mr. Case and Ms. Davies

The employment agreements of Mr. Case and Ms. Davies (which are described in greater detail under the heading “Employment Agreements”) were amended effective April 20, 2018 and April 19, 2018, respectively, to extend the term of those agreements through April 1, 2023. Prior to such amendments, the agreements would have expired (unless earlier terminated) on April 1, 2020. The amendments did not modify the compensation arrangements of either Mr. Case or Ms. Davies. Prior to approving these extensions, the Compensation Committee (and, with respect to Mr. Case, the Board) reviewed and considered the performance of Mr. Case and Ms. Davies during their respective periods of leadership with the Company (which, in both cases, exceeds the past decade), and the Company’s performance during those periods, including our significant shareholder return as compared to the S&P 500 and our peers. Although the Company’s general intent is to move away from fixed-term

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employment agreements for management employees, the Compensation Committee (and, with respect to Mr. Case, the Board) determined that securing the long-term commitment of our Chief Executive Officer and Chief Financial Officer was in the best interest of the Company and its shareholders, based on their established track record of success and consistent shareholder value creation.

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Executive Compensation

The executive compensation disclosure contained in this section reflects compensation information for the years ended December 31, 2018, December 31, 2017, and December 31, 2016 with respect to our “named executive officers” or “NEOs” for all years in which each NEO served in that capacity. The following Summary Compensation Table contains compensation information for the following NEOs: (1) Mr. Case, who served as our Chief Executive Officer during 2018 (and as our President from January 1, 2018 through May 14, 2018), (2) Ms. Davies, who served as our Chief Financial Officer during 2018, (3) Mr. Andersen, Mr. O’Connor, and Mr. Lieb, who were our three other most highly compensated executive officers serving as of December 31, 2018.

Summary Compensation Table for Fiscal Years 2018, 2017, and 2016

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For a description of cash allowances and cash bonuses paid to our NEOs in connection with the relocation, see footnote (c) below.

Ms. Davies, Mr. O’Connor, and Mr. Lieb participated in Aon’s executive health screening program in 2018. The amount included in “All Other Compensation” is the actual cost to Aon of the NEO’s use of this program, which was $7,537 for Ms. Davies, $11,250 for Mr. O’Connor, and $620 for Mr. Lieb.

Mr. O’Connor and Mr. Lieb received reimbursement for club dues of $3,630 and $7,272 respectively. Mr. Andersen also received an annual car allowance of $12,000. Mr. O’Connor and Mr. Andersen each received a non-cash gift for being named Co-President (grossed up for taxes in the amount of $398 and $480, respectively). Mr. O’Connor’s perquisites include the value (for airfare, hotel, gifts, spa services, and meals) related to his spouse’s attendance at a Company-related sales incentive event with Mr. O’Connor. These amounts are reflected in the perquisite column for these NEOs.

As part of Mr. Case’s employment agreement, Aon provides Mr. Case with life insurance coverage in the amount no less than $5,000,000 during the term of his agreement. This amount reflects the cost above and beyond the cost of life insurance that is provided to a typical Aon employee. For 2018, the cost was $20,635

We maintain an arrangement with NetJets for use of chartered aircraft and associated ground travel as necessary. Infrequently, an NEO will use a NetJets flight for personal purposes, or the spouse or guests of an NEO may accompany the executive when a NetJets flight is already going to a specific destination for a business purpose. In the case of a personal flight, the cost to the Company of such flight is reimbursed to the Company by the NEO. In the case of a spouse or other guest on a business flight, this has a minimal cost to the Company and, where applicable, the variable costs associated with the additional passenger are included in determining the aggregate incremental cost to the Company.

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Employment Agreements and Other Compensation Agreements

Mr. Case’s Employment Agreement

Aon entered into an Amended and Restated Employment Agreement with Gregory C. Case, our Chief Executive Officer, dated January 16, 2015, which would have expired April 1, 2020, unless terminated earlier. The agreement provided that Mr. Case would be employed as Aon’s President and Chief Executive Officer. The agreement was amended effective April 20, 2018 to extend the term of agreement through April 1, 2023 unless terminated earlier, and further amended effective May 15, 2018, to reflect Mr. Case’s title change to Chief Executive Officer. The agreement also provides that Mr. Case will be nominated for re-election as a member of the Board at each annual meeting of shareholders during the period of his employment.

Mr. Case’s agreement provides for an initial base salary of $1,500,000, subject to adjustment at the discretion of the Board, a target annual incentive bonus of not less than 200% of his base salary, subject to the provisions of the Shareholder-Approved Plan. The Board retains the discretion to determine Mr. Case’s actual bonus payment.

Pursuant to the agreement, in March 2015, Mr. Case received an additional award pursuant to Aon’s LPP for the performance period beginning January 1, 2015 and ending December 31, 2017 with a grant date target value of $15,000,000. This award was in addition to his regular annual long-term incentive award, and was earned based upon the same performance criteria and weightings as his regular annual long-term incentive award for 2015, which was also the same for other participants in the LPP for the performance period.

In addition, the agreement provides that Mr. Case will be provided with life insurance coverage in an amount no less than $5,000,000 during the term of the agreement. Under the agreement, Mr. Case has also agreed to maintain an investment position in Aon Class A Ordinary Shares equal to no less than 20 times his annual base salary.

Ms. Davies’s Employment Agreement

Aon entered into an Employment Agreement with Christa Davies, our Executive Vice President and Chief Financial Officer, dated as of October 3, 2007, which was amended effective March 27, 2012, February 20, 2015, and April 19, 2018, and which will expire on April 1, 2023 unless terminated earlier. The agreement provides that Ms. Davies will be employed as Aon’s Executive Vice President and Chief Financial Officer. The agreement reflects Ms. Davies’s then-current base salary of $900,000, which is subject to adjustment at the discretion of the Chief Executive Officer and the Compensation Committee of the Board, and a target annual incentive bonus of 150% of her base salary and foreign service allowance. In early 2019, the Committee approved an increase of $100,000 to Ms. Davies’s base salary, from $900,000 to $1,000,000.

Pursuant to the 2015 amendment, in March 2015, Ms. Davies received an additional award pursuant to Aon’s LPP for the performance period beginning on January 1, 2015 and ending December 31, 2017 with a grant date target value of $6,000,000. This award was in addition to her regular annual long-term incentive award, and was earned based upon the same performance criteria and weightings as her regular annual long-term incentive award for 2015, which was also the same for other participants in the LPP for the performance period.

Mr. Andersen’s Employment Agreement and Employment Letter

Aon entered into an Employment Agreement with Eric Andersen, our Co-President, dated as of October 1, 2013 that would have expired on October 1, 2018, unless terminated earlier. The agreement provided that Mr. Andersen would serve as Chief Executive Officer of Reinsurance and Retirement Solutions, Data and Analytics for a base salary of no less than $800,000, subject to adjustment, and a target annual incentive bonus of 100% of his base salary, subject to a cap of 300% of his base salary.

In connection with Mr. Andersen’s appointment as Aon’s Co-President and the expiration of Mr. Andersen’s employment agreement on October 1, 2018, and consistent with the Company’s general intent of moving away from the practice of entering into fixed-term employment agreements with our management employees, the Company and Mr. Andersen entered into an employment letter dated May 11, 2018. The employment letter provides that Mr. Andersen will serve as Aon’s Co-President, that his continued employment with the Company is on an at-will basis, and that he is eligible to participate in the Combined Severance Plan. The letter also provides that Mr. Andersen’s then-current base salary of $900,000 and his target annual incentive bonus are unchanged. In early 2019, the Committee approved an increase of $100,000 to Mr. Andersen’s base salary, from $900,000 to $1,000,000.

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Mr. O’Connor’s Employment Agreement and Employment Letter

Aon entered into an Employment Agreement with Michael J. O’Connor, our Co-President, dated as of March 29, 2013, that expired on March 1, 2018. The agreement provided that Mr. O’Connor would serve as Chief Executive Officer of Commercial Risk and Health Solutions for a base salary of no less than $800,000, subject to adjustment, and a target annual incentive bonus of 100% of his base salary, subject to a cap of 300% of his base salary.

In connection with the expiration of Mr. O’Connor’s employment agreement on March 1, 2018, and consistent with the Company’s general intent of moving away from the practice of entering into fixed-term employment agreements with our management employees, the Company and Mr. O’Connor entered into an employment letter dated March 1, 2018. The employment letter provided that Mr. O’Connor’s continued employment with the Company is on an at-will basis, and that he is eligible to participate in the Combined Severance Plan. The letter also provided that Mr. O’Connor’s then-current base salary of $900,000 and his target annual incentive bonus were unchanged. The letter was amended and restated effective May 15, 2018, to reflect his change in title to Aon’s Co-President. In early 2019, the Committee approved an increase of $100,000 to Mr. O’Connor’s base salary, from $900,000 to $1,000,000.

Mr. Lieb’s Employment Agreement and Employment Letter

Aon entered into an Employment Agreement with Peter Lieb, our Executive Vice President, General Counsel and Company Secretary, dated as of January 1, 2014, that would have expired on January 1, 2019, unless terminated earlier. The agreement replaced Aon’s prior agreement with Mr. Lieb and provided for a base salary of no less than $700,000, subject to adjustment, and a target annual incentive bonus of 100% of his base salary and foreign service allowance, subject to a cap of 300% of his base salary.

In connection with the expiration of Mr. Lieb’s employment agreement on January 1, 2019, and consistent with the Company’s general intent of moving away from the practice of entering into fixed-term employment agreements with our management employees, the Company and Mr. Lieb entered into an employment letter dated November 6, 2018. The employment letter provides that Mr. Lieb’s continued employment with the Company is on an at-will basis and that he is eligible to participate in the Combined Severance Plan. The letter also provides that Mr. Lieb’s base salary and target annual incentive bonus are unchanged.

International Assignment Letters

In connection with the Company’s redomestication in 2012, Aon entered into international assignment letters with each of Mr. Case, Ms. Davies, Mr. O’Connor, and Mr. Lieb. The letter describes the international assignment and sets forth the relocation benefits to the executive, which are described below. The letter is not intended to diminish the rights of the executive under his or her current employment arrangement; however, the letter provides by its terms that the executive’s acceptance of the international assignment, and repatriation thereafter, shall not give rise to any right to terminate for good reason (as such term is defined in the executive’s employment agreement, if applicable).

The letters for Mr. Case, Ms. Davies and Mr. Lieb were amended and extended in July 2014 for an additional two years, further amended and extended effective July 1, 2016 for an additional two years and effective July 1, 2018, for an additional one year. Mr. O’Connor’s 2012 letter was not extended and is no longer in effect; however, he is still eligible to receive tax preparation services in connection with compensation attributable to the period of time he was on international assignment.

Depending on each executive’s personal circumstances, and as disclosed in the tables above, the relocation packages, as amended, generally provide some or all of the following benefits:

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All of the relocation benefits are subject to recoupment if the executive officer resigns employment with the Company within two years of commencing the international assignment, or 12 months after the end thereof, and becomes employed by a direct competitor of the Company.

Grants of Plan-Based Awards in Fiscal Year 2018

The following table provides information on non-equity incentive plan awards, restricted share unit awards, and performance share unit awards granted in 2018 to each of the NEOs.