Appendix A Tax Equalization Policy

Dear Steve,

This international assignment letter (this “Letter”) restates and extends the term of your international assignment from Chicago, Illinois to London, England. Unless otherwise explicitly provided herein, this Letter shall govern the terms and conditions of your assignment from July 1, 2016 through June 30, 2018 (the “Term”), and during the Term shall supersede in their entirety both the letter entered into between you and Aon Corporation (the “Company”) dated January 12, 2012 and the extension letter entered into between you and the Company dated July 1, 2014 (collectively, your “Prior Assignment Letter”). The terms and conditions of your Prior Assignment Letter shall continue to apply through June 30, 2016.

We are committed to working with you to ensure that your international assignment continues to be as successful and effectively managed as possible. This Letter sets out the terms of your assignment and the assistance we are committed to provide in connection with your assignment, consistent with the approval of, and directions provided by, the Organization and Compensation Committee of the board of directors of Aon plc.

Your continued assignment is subject to your acceptance of the terms and conditions outlined in this Letter, which sets forth the entire agreement between you and the Company regarding your international assignment. To the extent that anything in this Letter conflicts with the amended and restated employment agreement entered into between you and the Company dated July 8, 2015 (the “Employment Agreement”) or the Company's employment-related policies and practices generally,  this Letter, once countersigned by you, will be a variation to your employment terms. Unless otherwise specified herein, your current employment terms and conditions will remain unchanged for the duration of the international assignment.

Once the Term is completed, you will return to the Company's offices in Chicago, Illinois, provided that the Company may, in consultation with you, extend or shorten your assignment and the Term according to business needs and/or your personal circumstances. Notwithstanding the foregoing, in the event that your assignment is extended beyond 36 months from the beginning of the Term, the Company reserves the right to "localize" your term by maintaining your international assignment and terminating the Term under this Letter.

Your assignment is conditional upon the Company being able to obtain and maintain the appropriate work permit, visa and/or other authorization documents for you to work and remain in London, England. The Company will cover the cost of obtaining and maintaining the appropriate work permit/visa for you. In addition, should you wish, the Company will also assist your spouse or partner in obtaining a work permit, visa and/or other authorization documents to work in London.

The changes to your compensation and benefits package during your international assignment, as described below, are designed to provide you with a level of income and benefits which do not disadvantage you in comparison to those you would have received in the United States. We have also taken into consideration any additional costs that you may reasonably incur as a result of living in London. Unless otherwise noted below as being an excluded or non-taxable benefit, the following benefits will be grossed up for applicable taxes to compensate you for any tax differential according to the Company’s tax equalization policy for international assignments (as described in Appendix A).

During the Term, you will receive an annual foreign service allowance of US$105,000. While on assignment, your annual foreign service allowance will be added to your base salary for purposes of determining your annual target incentive opportunity. The allowance will be paid semi-monthly via your U.S. payroll.

During the Term, you will receive an annual car allowance of US$23,500. This allowance will be paid semi-monthly via your U.S. payroll.

It is likely that all or a portion of your earned income during any given U.K. tax year will be subject to tax in the U.K. The Company applies a tax equalization policy (as described in Appendix A) which is designed to ensure the income and social taxes you pay will be no more than what you would have paid had all of your earnings been taxable solely in the U.S.

The Company will also provide you with enhanced tax preparation, financial planning and expatriate services for the tax years covered by the international assignment and tax years for which international earnings are taxed by U.K. tax authorities following repatriation at the conclusion of the Term (or upon your termination of employment without Cause or for Good Reason while on assignment)

Your work schedule, work hours and observed holidays will follow the practice in London.

Should you elect to resign from the Company to work with a direct competitor, during your assignment or up to 12 months after the end of the Term, the Company reserves the right to require repayment of all expatriate allowances you received in the preceding 12 months. You agree that the Company may set off any such amounts against any amount the Company owes you on or after termination of your employment.

Should you depart the Company due to mutual consent or for Good Reason (as defined in your Employment Agreement) or if a comparable U.S.-based role is not available at the completion of your assignment, this repayment agreement will not apply.

Notwithstanding the foregoing, if your employment is terminated without Cause or for Good Reason (as such terms are defined in your Employment Agreement) during the Term, the following provisions will apply during the Term and thereafter for as long as you continue to abide by the conditions of Section 5(b) and 5(c) of your Employment Agreement, comply in all material respects with Section 7 of your Employment Agreement, and sign and return the release required under Section 4(b)(ii) of your Employment Agreement, in each case, as and to the extent provided as follows:

For the avoidance of doubt, should you be terminated for Cause or voluntarily terminate your employment without mutual consent while on assignment, you will bear all relocation and other costs arising after your termination for Cause or resignation date.

At the end of your assignment, the Company will endeavor to repatriate you into a position consistent with your then current employment agreement, if applicable, and in accordance with your capabilities, interest and career potential. Your relocation will be managed in accordance with the provisions of the Company's policy.

The Company will pay the transportation and moving cost for you and your family back to the U.S. at the end of the Term (or once your assignment ends due to your termination of employment without Cause or for Good Reason, or due to your resignation after attaining age 55) in accordance with the Company's international relocation policy.

Each related entity of the Company is a third party beneficiary of this Letter, and each of them has the full right and power to enforce rights, interests and obligations under this Letter without limitation or other restriction.

No failure or delay by any party in exercising any right, power or remedy under this Letter shall operate as a waiver thereof, nor shall any single or particular exercise of the same preclude any further exercise thereof or the exercise of any other right, power or remedy. Without limiting the foregoing, no waiver by any party of any breach of any provision of this Letter shall be deemed to be a waiver of any subsequent breach of that or any other provision of this Letter.

While it is anticipated that all or most of your compensation from the Company will be subject to a hypothetical tax deduction rather than actual tax withholdings, all amounts paid pursuant to this Letter shall be subject to deductions and withholding for taxes (national, local, foreign or otherwise) to the extent required by applicable law.

We intend that this Letter and the benefits provided hereunder be interpreted and construed to be exempt from or otherwise comply with the applicable requirements of Section 409A of the U.S. Internal Revenue Code of 1986, as amended, and all Treasury regulations and guidance issued thereunder ("Code Section 409A"), including the exceptions for short-term deferrals, separation pay arrangements, reimbursements, and in-kind distributions. To the extent that any provision of this Letter would fail to comply with the applicable requirements of Code Section 409A, the Company may, in its sole and absolute discretion and without requiring your consent, make such modifications to the Letter and/or payments to be made thereunder to the extent it determines necessary or advisable to comply with the requirements of Code Section 409A. Notwithstanding any provision of this Letter to the contrary, if you are a “specified employee” within the meaning of Code Section 409A, any payments or arrangements due upon a termination of your employment that are subject to the requirements of Code Section 409A shall be delayed and paid or provided on the earlier of six months after your termination of employment or the date of your death. Upon the expiration of this delay period, all payments and benefits delayed shall be paid or reimbursed to you in a lump sum, and any remaining payments and benefits due under this Letter shall be paid or provided in accordance with the terms of this Letter. For purposes of applying the provisions of Code Section 409A, each separately identifiable amount to which you are entitled will be treated as a separate payment. A termination of employment shall not be deemed to have occurred for purposes of any provision of this Letter providing for payment of amounts subject to Code Section 409A upon or following a termination of employment unless the termination is also a “separation from service” under Code Section 409A.

This Letter will be construed in accordance with and governed by the laws of the State of Illinois, without regard to the choice of law principles thereof. Any suit, action or other legal proceeding arising out of or relating to this Letter shall be brought exclusively in the Federal or state courts located in the State of Illinois. You agree to submit to personal jurisdiction in the foregoing courts and to venue in those courts. You further agree to waive all legal challenges and defenses to the propriety of a forum in Chicago, Illinois and to the application of Federal or Illinois law therein.

Please confirm acceptance of the terms set out in this Letter by signing below and returning a copy of the signed Letter to me.

By signing below, I acknowledge receipt of this Letter; I accept the terms and conditions contained herein; and I consent to this international assignment. For the avoidance of doubt, nothing in this Letter is intended to diminish my rights under my Employment Agreement, or any plan or equity-based award agreement, and I will continue to be entitled to the rights and benefits under any such arrangement during this international assignment. Notwithstanding the foregoing, I acknowledge and agree that my consent herein to the international assignment, and my acceptance of this particular international assignment to London and my repatriation thereafter, shall not give rise to any right to terminate for Good Reason (as defined in my Employment Agreement, if applicable, or any other agreement between me and the Company) now or hereafter.

I further acknowledge that I have read and agree to be bound by the Company's tax equalization policy (as set forth on Appendix A). With regard to that policy, I specifically agree acknowledge and agree that: if I owe any monies to the Company I will make payment of such monies to the Company within 60 days of receiving notification of the amount due; and authorize the Company to deduct (or reduce from my earnings) any amounts owed under this policy from my paycheck where permitted by law.

The Company will apply the following tax equalization policy to ensure that the income and social taxes you pay will be no more than that you would have paid had all of your earnings been taxable solely in the U.S. For the avoidance of doubt, the policy does not provide for the grossing up for U.S. income and social taxes on the relocation benefits described in the Letter.

The Company will determine an estimate of the tax liability you would have paid in the U.S. on your earnings from the Company, known as your "hypothetical'' tax liability, and will deduct this estimated hypothetical tax from your monthly earnings via the Company's U.S. payroll. This policy will not protect you in your capacity as a shareholder of the Company from capital gains recognized pursuant to U.S. federal income tax as a result of the merger; however, your earnings related to granting or vesting of equity-based awards during your international assignment will be covered by this policy.

Hypothetical tax is paid on salary and on any other income paid to you by the Company (e.g. bonus) or compensation recognized by you (e.g., granting or vesting of stock-based incentives). Please note, for the avoidance of doubt, the Company will deduct hypothetical tax from your income at the point the income is paid to you and not by reference to the payment date that might have applied had you not taken up the assignment.

Please note that you will be responsible for the cost of any tax or additional charges arising in any tax jurisdiction on any personal income or gains, spousal income or any other U.S. source income.

For the duration of your assignment and any tail period required, the Company will authorize and pay for a tax adviser to: (1) prepare your joint or individual U.S. Federal and State, and U.K. tax returns as required; and (2), reconcile the hypothetical tax deductions made from your earnings.

If the amount of your final hypothetical tax liability to the Company is greater than the amount of any estimated hypothetical tax payments deducted by the Company from your salary or other payments, then you will be required to pay the additional hypothetical tax to the Company within 60 days of the relevant tax returns being finalized. If it is less, then the Company will reimburse any excess to you within 60 days.

Provided you meet your obligations to the Company in respect. of your hypothetical fax liability and provide such information and assistance as the Company and/or its designated tax adviser shall require in order to resolve your tax affairs on a timely basis and within the filing deadlines set down by the applicable tax authorities, the Company will pay any actual tax or social security liability arising in respect of your earned income.

Should you delay providing the necessary information to the tax advisers you will be responsible for any additional fees and/or penalties that arise as a result of the delay.

Although the Company will retain and pay all external tax adviser on your behalf to prepare your tax returns and to calculate your· tax equalization calculations, it remains your personal obligation to file such returns within the applicable time limits and to abide by the tax laws in both the U.S. and U.K. The external tax adviser will provide regular information regarding your obligations and filing schedules.