# EDGAR Filing Document

**Accession Number:** 0000315293
**File Stem:** 0001193125-23-054079
**Filing Date:** 2023-2
**Character Count:** 228140
**Document Hash:** 2e0a17f75ae8501edcf44121991cf57c
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-23-054079.hdr.sgml**: 20230228

**ACCESSION NUMBER**: 0001193125-23-054079

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 24

**CONFORMED PERIOD OF REPORT**: 20230223

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20230228

**DATE AS OF CHANGE**: 20230228

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Aon plc
- **CENTRAL INDEX KEY:** 0000315293
- **STANDARD INDUSTRIAL CLASSIFICATION:** INSURANCE AGENTS BROKERS & SERVICES [6411]
- **IRS NUMBER:** 981539969
- **STATE OF INCORPORATION:** L2
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-07933
- **FILM NUMBER:** 23686810

**BUSINESS ADDRESS:**
- **STREET 1:** METROPOLITAN BUILDING
- **STREET 2:** JAMES JOYCE STREET
- **CITY:** DUBLIN 1
- **STATE:** L2
- **ZIP:** D01 K0Y8
- **BUSINESS PHONE:** 35312666000

**MAIL ADDRESS:**
- **STREET 1:** METROPOLITAN BUILDING
- **STREET 2:** JAMES JOYCE STREET
- **CITY:** DUBLIN 1
- **STATE:** L2
- **ZIP:** D01 K0Y8

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** AON CORP
- **DATE OF NAME CHANGE:** 19920703

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** COMBINED INTERNATIONAL CORP
- **DATE OF NAME CHANGE:** 19870504

?xml version="1.0" encoding="utf-8" ? 8-K

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### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

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### FORM 8-K

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#### CURRENT REPORT

#### Pursuant to Section 13 or 15(d)

#### of the Securities Exchange Act of 1934

#### Date of Report (Date of earliest event reported): February 23, 2023

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## Aon plc

#### (Exact name of registrant as specified in its charter)

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| | | |
|:---|:---|:---|
| **Ireland** | **1-7933** | **95-1539969** |
| **(State or other jurisdiction**<br> **of incorporation)** | **(Commission**<br> **File Number)** | **(IRS Employer**<br> **Identification No.)** |

---

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| | |
|:---|:---|
| **Metropolitan Building, James Joyce Street**<br> **Dublin 1, Ireland** | **D01 K0Y85** |
| **(Address of principal executive offices)** | **(Zip Code)** |

---

#### Registrant's telephone number, including area code: +353 1 266 6000

#### Former name or former address, if changed since last report: Not Applicable

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2 below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

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| | | |
|:---|:---|:---|
| **Title of each class** | **Trading**<br> **Symbol(s)** | **Name of each exchange**<br> **on which registered** |
| Class A Ordinary Shares, $0.01 nominal value | AON | New York Stock Exchange |
| Guarantees of Aon plc's 4.000% Senior Notes due<br> 2023 | AON23 | New York Stock Exchange |
| Guarantees of Aon plc's 3.500% Senior Notes due<br> 2024 | AON24 | New York Stock Exchange |
| Guarantees of Aon plc's 3.875% Senior Notes due<br> 2025 | AON25 | New York Stock Exchange |
| Guarantees of Aon plc's 2.875% Senior Notes due<br> 2026 | AON26 | New York Stock Exchange |
| Guarantees of Aon Corp. and Aon Global Holdings plc's 2.850% Senior Notes due 2027 | AON27 | New York Stock Exchange |
| Guarantees of Aon Corp. and Aon Global Holdings plc's 2.050% Senior Notes due 2031 | AON31 | New York Stock Exchange |
| Guarantees of Aon Corp. and Aon Global Holdings plc's 2.600% Senior Notes due 2031 | AON31A | New York Stock Exchange |
| Guarantees of Aon Corp. and Aon Global Holdings plc's 5.000% Senior Notes due 2032 | AON32 | New York Stock Exchange |
| Guarantees of Aon plc's 4.250% Senior Notes due<br> 2042 | AON42 | New York Stock Exchange |
| Guarantees of Aon plc's 4.450% Senior Notes due<br> 2043 | AON43 | New York Stock Exchange |
| Guarantees of Aon plc's 4.600% Senior Notes due<br> 2044 | AON44 | New York Stock Exchange |
| Guarantees of Aon plc's 4.750% Senior Notes due<br> 2045 | AON45 | New York Stock Exchange |
| Guarantees of Aon Corp. and Aon Global Holdings plc's 2.900% Senior Notes due 2051 | AON51 | New York Stock Exchange |
| Guarantees of Aon Corp. and Aon Global Holdings plc's 3.900% Senior Notes due 2052 | AON52 | New York Stock Exchange |

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Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

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| | |
|:---|:---|
| **Item 8.01** | **Other Events.**  |

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On February 23, 2023, Aon Corporation, a Delaware corporation ("Aon Corporation"), Aon Global Holdings plc, a public limited company formed under the laws of England and Wales ("AGH" and, together with Aon Corporation, the "Issuers"), Aon plc, an Irish public limited company ("Aon plc") and Aon Global Limited, a private limited company formed under the laws of England and Wales, and prior to its re-registration, a public limited company formed under the laws of England and Wales named Aon plc ("AGL" and, together with Aon plc, the "Guarantors" and each, a "Guarantor"), entered into an underwriting agreement (the "Underwriting Agreement") with Morgan Stanley & Co. LLC, BofA Securities, Inc. and HSBC Securities (USA) Inc. as representatives of the several underwriters named therein, with respect to the offering and sale by Aon Corporation and AGH of $750,000,000 aggregate principal amount of their 5.350% Senior Notes due 2033 (the "Notes") under the Registration Statement on Form S-3 (Registration Nos. 333-238189, 333-238189-01, 333-238189-02 and 333-238189-03). Each Guarantor has fully and unconditionally, jointly and severally, guaranteed the Notes pursuant to the Indenture (as defined below) (collectively, the "Guarantees" and, together with the Notes, the "Securities"). The Securities were issued pursuant to an indenture, dated December 3, 2018, as amended and restated on April 1, 2020, as further amended and supplemented by a fifth supplemental indenture on February 28, 2023 (together, the "Indenture"), among Aon Corporation, AGH, the Guarantors and The Bank of New York Mellon Trust Company, N.A., as trustee (the "Trustee").

The net proceeds from the offering, after deducting the underwriting discount and estimated offering expenses payable by the Issuers, were approximately $743,535,950. Aon Corporation and AGH intend to use the net proceeds from the offering for general corporate purposes.

The Underwriting Agreement and the Fifth Indenture Supplement are filed as Exhibits 1.1 and 4.2 to this Current Report on Form 8-K, respectively, and are incorporated by reference herein. The form of the Notes (including the Guarantees) is filed as Exhibit 4.3 to this Current Report on Form 8-K and is incorporated by reference herein.

In connection with the issuance of the Securities, Sidley Austin LLP is filing the legal opinion attached as Exhibit 5.1 to this Current Report on Form 8-K, Freshfields Brukhaus Deringer LLP is filing the legal opinion attached as Exhibit 5.2 and Matheson is filing the legal opinion attached as Exhibit 5.3 to this Current Report on Form 8-K.

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| | |
|:---|:---|
| **Item 9.01** | **Financial Statements and Exhibits.**  |

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(d) Exhibits.

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| | |
|:---|:---|
| Exhibit<br>No. | Description |
| 1.1 | [Underwriting Agreement, dated February 23, 2023, among Aon Corporation, AGH, Aon plc and AGL, and Morgan Stanley & Co. LLC, BofA Securities, Inc. and HSBC Securities (USA) Inc. as representatives of the several underwriters named therein.](d474704dex11.htm) |
| 4.1 | [Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, AGL, AGH and the Trustee (amending and restating the Indenture, dated December 3, 2018, among Aon Corporation, AGL and the Trustee) (included in Exhibit 4.6 to the Current Report on Form 8-K12B filed by Aon plc on April 1, 2020).](http://www.sec.gov/Archives/edgar/data/315293/000119312520093512/d867242dex46.htm) |
| 4.2 | [Fifth Indenture Supplement, dated as of February 28, 2023, among Aon Corporation, AGH, the Guarantors and the Trustee.](d474704dex42.htm) |
| 4.3 | [Form of 5.350% Senior Notes due 2033 (including the Guarantees) (included in Exhibit 4.2).](d474704dex42.htm) |
| 5.1 | [Opinion of Sidley Austin LLP.](d474704dex51.htm) |
| 5.2 | [Opinion of Freshfields Brukhaus Deringer LLP.](d474704dex52.htm) |
| 5.3 | [Opinion of Matheson.](d474704dex53.htm) |
| 23.1 | [Consent of Sidley Austin LLP (included in Exhibit 5.1).](d474704dex51.htm) |
| 23.2 | [Consent of Freshfields Brukhaus Deringer LLP (included in Exhibit 5.2).](d474704dex52.htm) |
| 23.3 | [Consent of Matheson (included in Exhibit 5.3).](d474704dex53.htm) |
| 104 | Cover Page Interactive Data File (formatted in iXBRL in Exhibit 101). |

---

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#### SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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| | | | |
|:---|:---|:---|:---|
| Date: February 28, 2023 | **AON PLC** | **AON PLC** | **AON PLC** |
|  | By: | /s/ Julie Cho | /s/ Julie Cho |
|  |  | Name: | Julie Cho |
|  |  | Title: | Assistant Company Secretary |

---

## Exhibit 1.1

**Exhibit 1.1** 

**Aon Corporation** 

**Aon Global Holdings plc** 

**Aon plc** 

**Aon Global Limited** 

**$750,000,000 5.350% Senior Notes due 2033** 

**<u>UNDERWRITING AGREEMENT</u>**

February 23, 2023

Morgan Stanley & Co. LLC

BofA Securities, Inc.

HSBC Securities (USA) Inc.

*As Representatives (the "****Representatives****") of the several Underwriters listed in Exhibit A hereto* 

c/o Morgan Stanley & Co. LLC

1585 Broadway

New York, New York 10036

c/o BofA Securities, Inc.

One Bryant Park

New York, New York 10036

c/o HSBC Securities (USA) Inc.

452 Fifth Avenue

New York, New York 10018

Ladies and Gentlemen:

1. *Introductory*. Aon Corporation, a Delaware corporation (the "**Company**") and Aon Global
Holdings plc, a public limited company formed under the laws of England and Wales (the "**Co-Issuer**" and, together with the Company, the "**Issuers,**" and each, an
" **Issuer** "), agree with the several Underwriters named in Exhibit A hereto (the "**Underwriters**") to issue and sell to the several Underwriters $750,000,000 principal amount of their 5.350% Senior Notes due 2033 (the
" **Notes** "), to be issued under an indenture dated as of December 3, 2018 (the "**Base Indenture** "), as amended and restated by the amended and restated indenture dated as of April 1, 2020 (the
" **A&R Indenture**") among the Issuers, the Guarantors (as defined below) and The Bank of New York Mellon Trust Company, N.A., as trustee (the "**Trustee** "), and as further supplemented by a supplemental
indenture to be dated as of February 28, 2023 (the "**Supplemental Indenture**" and, together with the Base Indenture and the Supplemental Indenture, the "**Indenture**") among the Issuers, the Guarantors and the
Trustee. The Notes will be fully and unconditionally guaranteed as to the payment of principal and interest by Aon plc, a public limited company formed under the laws of Ireland ()"**Aon plc**") and Aon Global Limited (formerly known as
Aon plc and as further defined below) ()"**AGL**" and, together with Aon plc, the "**Guarantors**," and each, a "**Guarantor**," and such guarantees, the "**Guarantees** "). "**Aon plc**" refers to (i) for time periods prior to the completion of the Reorganization (as defined in the General Disclosure Package), AGL, and (ii) for time periods on and after the completion of the Reorganization, Aon plc; and
" **AGL**" refers to (i) for time periods after July 15, 2020, the date of re-registration, Aon Global Limited, a private limited company formed under the laws of England and Wales, and
(ii) for the time periods prior to the date of re-registration, Aon plc, a public limited company formed under the laws of England and Wales and the former publicly traded parent company of the Aon group.
The Notes, together with the Guarantees, are referred to in this Agreement as the "**Securities**."

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2. *Representations and Warranties of the Issuers*. Each of the *Issuers* and the Guarantors represents
and warrants to, and agrees with, the several Underwriters that:

(a) *Filing and Effectiveness of Registration Statement; Certain Defined Terms*. The Issuers and the
Guarantors have filed with the Commission a registration statement on Form S-3 (Nos. 333-238189, 333-238189-01, 333-238189-02 and 333-238189-03), including a related prospectus or prospectuses, covering the registration of the Securities under the Act, which has become effective. "**Registration Statement**" at any
particular time means such registration statement in the form then filed with the Commission, including any amendment thereto, any document incorporated by reference therein and all 430B Information and all 430C Information with respect to such
registration statement, that in any case has not been superseded or modified. "**Registration Statement**" without reference to a time means such registration statement as of the time as of which such registration statement was declared
effective by the Commission or has become effective upon filing pursuant to Rule 462(c). For purposes of this definition, 430B Information shall be considered to be included in the Registration Statement as of the time specified in Rule 430B.

For purposes of this Agreement:

"**430B Information**" means information included in a prospectus then deemed to be a part of the Registration Statement pursuant to Rule 430B(e) or retroactively deemed to be a part of the Registration Statement pursuant to Rule 430B(f).

"**430C Information**" means information included in a prospectus then deemed to be a part of the Registration Statement pursuant to Rule 430C.

"**Act**" means the Securities Act of 1933, as amended.

"**Applicable Time**" means 3:25 p.m. (New York City time) on the date of this Agreement. 

"**Closing Date**" has the meaning set forth in Section 3 hereof.

"**Commission**" means the Securities and Exchange Commission.

"**Exchange Act**" means the Securities Exchange Act of 1934, as amended.

"**Final Prospectus**" means the Statutory Prospectus that discloses the public offering price, other 430B Information and other final terms of the Securities, and otherwise satisfies Section 10(a) of the Act.

"**General Use Issuer Free Writing Prospectus**" means any Issuer Free Writing Prospectus that is intended for general distribution to prospective investors, as evidenced by its being so specified in Exhibit B to this Agreement.

"**Issuer Free Writing Prospectus**" means any "issuer free writing prospectus," as defined in Rule 433, relating to the Securities in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Issuers' records pursuant to Rule 433(g).

"**Limited Use Issuer Free Writing Prospectus**" means any Issuer Free Writing Prospectus that is not a General Use Issuer Free Writing Prospectus. 

"**Rules and Regulations**" means the rules and regulations of the Commission.

"**Securities Laws**" means, collectively, the Sarbanes-Oxley Act of 2002, as amended and all rules and regulations promulgated thereunder or implementing the provisions thereof ("**Sarbanes-Oxley**"), the Act, the Exchange Act, the Trust Indenture Act, the Rules and Regulations, the auditing principles, rules, standards and practices applicable to auditors of "issuers" (as defined in Sarbanes-Oxley) promulgated or approved by the Public Company Accounting Oversight Board and, as applicable, the rules of The New York Stock Exchange ("**Exchange Rules**").

"**Statutory Prospectus**" with reference to any particular time means the prospectus relating to the Securities that is included in the Registration Statement immediately prior to that time, including all 430B Information and all 430C Information with respect to the Registration Statement. For purposes of the foregoing definition, 430B Information shall be considered to be included in the Statutory Prospectus only as of the actual time that such form of prospectus (including a prospectus supplement) is filed with the Commission pursuant to Rule 424(b) and not retroactively.

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"**Trust Indenture Act**" means the Trust Indenture Act of 1939, as amended.

Unless otherwise specified, a reference to a "rule" is to the indicated rule under the Act.

(b) *Compliance with Act Requirements*. (i) (A) At the time the Registration Statement initially became
effective, (B) at the time of each amendment thereto for the purposes of complying with Section 10(a)(3) of the Act (whether by post-effective amendment, incorporated report or form of prospectus)
and (C) on the Closing Date, the Registration Statement conformed and will conform in all material respects to the requirements of the Act and the Rules and Regulations and did not and will not include any untrue statement of a material fact or
omit to state any material fact required to be stated therein or necessary to make the statements therein not misleading and (ii) (A) on its date, (B) at the time of filing the Final Prospectus pursuant to Rule 424(b) and (C) on
the Closing Date, the Final Prospectus will conform in all material respects to the requirements of the Act and the Rules and Regulations, and will not include any untrue statement of a material fact or omit to state any material fact required to be
stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to (i) that part of the Registration Statement that constitutes the
Statement of Eligibility and Qualification (Form T-1) of the Trustee under the Trust Indenture Act and (ii) statements in or omissions from any such document based upon written information furnished to
the Issuers by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information is that described as such in Section 8(b) hereof.

(c) *Automatic Shelf Registration Statement*. (i) *Well-Known Seasoned Issuer Status*. (A) At
the time of initial filing of the Registration Statement, (B) at the time of the most recent amendment thereto for the purposes of complying with Section 10(a)(3) of the Act (whether such amendment was by post-effective amendment,
incorporated report filed pursuant to Section 13 or 15(d) of the Exchange Act or form of prospectus), and (C) at the time the Issuers, the Guarantors or any person acting on their respective behalf (within the meaning, for this clause
only, of Rule 163(c)) made any offer relating to the Securities in reliance on the exemption of Rule 163, each of the Issuers and the Guarantors was a "well-known seasoned issuer" as defined in Rule 405, including not having been an
"ineligible issuer" as defined in Rule 405.

(ii) *Effectiveness of Automatic Shelf Registration Statement*. The Registration Statement is an
"automatic shelf registration statement," as defined in Rule 405, that initially became effective within three years of the date of this Agreement.

(iii) *Eligibility to Use Automatic Shelf Registration Form*. Neither the Issuers nor any of the Guarantors has
received from the Commission any notice pursuant to Rule 401(g)(2) objecting to use of the automatic shelf registration statement form.

(iv) *Filing Fees*. An Issuer or a Guarantor has paid or shall pay the required Commission filing fees relating
to the Securities within the time required by Rule 456(b)(1) without regard to the proviso therein and otherwise in accordance with Rules 456(b) and 457(r).

(d) *Ineligible Issuer Status*. (i) At the earliest time after the filing of the Registration Statement
that the Issuers, the Guarantors or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2)) of the Securities and (ii) at the date of this Agreement, each of the Issuers and the Guarantors was not and is not
an "ineligible issuer," as defined in Rule 405.

(e) *General Disclosure Package*. As of the Applicable Time, neither (i) the General Use Issuer Free
Writing Prospectus(es) issued at or prior to the Applicable Time, the preliminary prospectus supplement, dated February 23, 2023, including the base prospectus, dated May 12, 2020 (which is the most recent Statutory Prospectus distributed
to investors generally), any document incorporated by reference therein and the other information, if any, stated in Exhibit B to this Agreement to be included in the General Disclosure Package, all considered together (collectively, the
" **General Disclosure Package** "), nor (ii) any individual Limited Use Issuer Free Writing Prospectus, when considered together with the General Disclosure Package, included any untrue statement of a material fact or omitted

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to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from the General Disclosure Package in reliance upon and in conformity with written information furnished to the Issuers by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8(b) hereof.

(f) *Issuer Free Writing Prospectuses*. Each Issuer Free Writing Prospectus, as of its issue date and at all
subsequent times through the Closing Date or until any earlier date that the Issuers notified or notify the Representatives as described in the next sentence, did not, does not and will not include any information that conflicted, conflicts or will
conflict with the information then contained in the Registration Statement. If at any time following issuance of an Issuer Free Writing Prospectus and prior to the Closing Date there occurred or occurs an event or development as a result of which
such Issuer Free Writing Prospectus conflicted or would conflict with the information then contained in the Registration Statement or as a result of which such Issuer Free Writing Prospectus, if republished immediately following such event or
development, would, when considered together with the rest of the General Disclosure Package, include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in the
light of the circumstances under which they were made, not misleading, (i) the Issuers have promptly notified or will promptly notify the Representatives and (ii) the Issuers have promptly amended or will promptly amend or supplement such
Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement or omission.

(g) *Good Standing of the Issuers and the Guarantors*. Each of the Issuers and the Guarantors has been duly
incorporated or formed, as applicable, and is existing and, where such concept applies, in good standing under the laws of the jurisdiction of its incorporation, with corporate power and authority, where such concept applies, to own its properties
and conduct its business as described in the General Disclosure Package; and each of the Issuers and the Guarantors is duly qualified to do business as a foreign corporation in good standing, where such concept applies, in all other jurisdictions in
which its ownership or lease of property or the conduct of its business requires such qualification, except where the failure to so qualify or be in good standing would not, individually or in the aggregate, reasonably be expected to result in a
material adverse effect or any development or event involving a prospective material adverse effect on the financial condition, results of operations, business or properties of the Issuers, the Guarantors and their respective subsidiaries taken as a
whole ()"**Material Adverse Effect** ").

(h) *Significant Subsidiaries*. Each subsidiary of Aon plc designated on Exhibit C hereto (each, a
" **Significant Subsidiary**") (i) has been duly incorporated and is existing and in good standing, where such concept applies, under the laws of the jurisdiction of its incorporation and (ii) has the corporate power and authority
to own its properties and conduct its business as described in the General Disclosure Package, except, in the case of clause (h) above, as would not reasonably be expected to have a Material Adverse Effect; and each Significant Subsidiary is
duly qualified to do business as a foreign corporation in good standing, where such concept applies, in all other jurisdictions in which its ownership or lease of property or the conduct of its business requires such qualification, except where the
failure to so qualify or be in good standing would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect; all of the issued and outstanding capital stock of each Significant Subsidiary has been duly
authorized and validly issued and is fully paid and nonassessable; and except as described in the General Disclosure Package, the capital stock of each Significant Subsidiary owned by Aon plc, directly or through subsidiaries, is owned free from
liens, encumbrances and security interests.

(i) *Execution and Delivery of Indenture*. The Indenture has been duly authorized, and each of the Base
Indenture and the A&R Indenture has been executed and delivered by each of the Issuers and the Guarantors; When the Supplemental Indenture has been duly executed by each of the Issuers and the Guarantors (assuming due authorization, execution
and delivery of the Indenture by the Trustee), the Indenture will constitute a valid and binding agreement of each of the Issuers and the Guarantors, enforceable against the Issuers and the Guarantors in accordance with its terms; the Indenture has
been qualified under the Trust Indenture Act; the Notes and Guarantees have been duly authorized and, when the Notes and the Guarantees are delivered and paid for pursuant to this Agreement on the Closing Date, such Notes will have been duly
executed, authenticated, issued and delivered by each of the Issuers and the Guarantors (assuming that the Notes have been authenticated in the manner provided for in the Indenture) and such Guarantees will have been duly executed, issued and
delivered, and the Notes and the Guarantees will conform in all material respects to the information in the General Disclosure Package and to the description of the Securities contained in the Final Prospectus and the Indenture, and the Securities
will constitute valid and legally binding obligations of the Issuers or the Guarantors, as the case may be, enforceable in accordance with their terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar
laws of general applicability relating to or affecting creditors' rights and to general equity principles.

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(j) *Absence of Further Requirements*. No consent, approval, authorization or order of, or filing or
registration with, any person (including any governmental agency or body or any court) is required for the consummation of the transactions contemplated by this Agreement or the Indenture in connection with the offering, issuance and sale of the
Securities by the Issuers and the Guarantors, except such as have been obtained or made and such as may be required under federal or state securities laws and except as disclosed or contemplated in the General Disclosure Package and the Final
Prospectus.

(k) *Absence of Defaults and Conflicts Resulting from Transaction*. The issuance and sale by the Issuers and
Guarantors of the Securities and the execution and delivery by the Issuers and Guarantors of this Agreement, and the performance by the Issuers and Guarantors of their respective obligations under this Agreement, the Indenture and the Securities,
will not contravene (i) the articles of association, certificate of incorporation or by-laws of the Issuers or the Guarantors, as applicable, (ii) any agreement or other instrument filed as a
"material contract" with respect to Aon plc's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 or (iii) any provision of material applicable law or any material
judgment, order or decree of any governmental body, agency or court having jurisdiction over the Issuers, the Guarantors or any of their respective subsidiaries.

(l) *Absence of Existing Defaults and Conflicts*. Neither the Issuers nor any of the Guarantors is in
violation of its organizational documents or in default (or with the giving of notice or lapse of time would be in default) in the performance or observance of any obligation, agreement, covenant or condition contained in any contract, indenture,
mortgage, loan agreement, note, lease or other instrument or agreement to which it is a party or by which it or any of its properties may be bound, which violation or default would, individually or in the aggregate, reasonably be expected to result
in a Material Adverse Effect.

(m) *Authorization of Agreement*. This Agreement has been duly authorized, executed and delivered by each of
the Issuers and the Guarantors.

(n) *Possession of Licenses and Permits*. The Issuers, the Guarantors and their respective subsidiaries
possess such certificates, authorities or permits issued by the appropriate state, federal or foreign regulatory agencies or bodies necessary to conduct the business now operated by them as described in the Registration Statement, the General
Disclosure Package and the Final Prospectus and, to the knowledge of the Issuers and the Guarantors, have not received any notice of proceedings relating to the revocation or modification of any certificates, authorities or permits, except where the
failure to possess such certificates, authorities or permits would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(o) *Absence of Labor Dispute*. No labor dispute with the employees of the Issuers, Guarantors or any of their
respective subsidiaries exists or, to the knowledge of the Issuers and the Guarantors, is imminent that would reasonably be expected to have a Material Adverse Effect.

(p) *Accurate Disclosure*. The statements in the General Disclosure Package and the Final Prospectus under the
headings "Description of Debt Securities and Guarantees," "Material U.S. Federal Income Tax Consequences," "Certain U.K. Tax Consequences" and "Certain Irish Tax Consequences," insofar as such statements
summarize legal matters, agreements, documents or proceedings discussed therein, are, in all material respects, accurate and fair summaries of such legal matters, agreements, documents or proceedings and present the information required to be shown.

(q) *Absence of Stabilization or Manipulation*. Neither the Issuers nor any of the Guarantors has taken,
directly or indirectly, any action that is designed to or that has constituted or that would reasonably be expected to cause or result in the stabilization or manipulation of the price of any security of the Issuers in connection with the offering
of the Securities.

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(r) *Internal Controls*. There are no material weaknesses in Aon plc's internal controls over financial
reporting ()"**Internal Controls** "). Except as disclosed in the General Disclosure Package, since the date of the latest audited financial statements included in the General Disclosure Package, there has been no change in Aon plc's
internal control that has materially affected, or is reasonably likely to materially affect, Aon plc's Internal Controls. Aon plc maintains a system of Internal Controls, including, but not limited to, disclosure controls and procedures,
internal controls over accounting matters and financial reporting, an internal audit function and legal and regulatory compliance controls, that comply with Rule 13a-15 under the Exchange Act and are
sufficient to provide reasonable assurances that (i) transactions are executed in accordance with management's general or specific authorizations, (ii) transactions are recorded as necessary to permit preparation of financial
statements in conformity with U.S. General Accepted Accounting Principles and to maintain accountability for assets, (iii) access to assets is permitted only in accordance with management's general or specific authorization and
(iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences.

(s) *Litigation*. There are no legal or governmental proceedings pending or, to the knowledge of the Issuers
or Guarantors, threatened to which the Issuers, the Guarantors or any of their respective subsidiaries is a party or to which any of the properties of the Issuers, the Guarantors or any of their respective subsidiaries is subject, other than
proceedings fairly summarized in all material respects in the General Disclosure Package and proceedings which would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect or materially impair the power or
ability of the Issuers or the Guarantors to perform its obligations under this Agreement, the Indenture or the Securities or to consummate the offering contemplated hereby.

(t) *Financial Statements*. The financial statements included in the Registration Statement, the General
Disclosure Package and the Final Prospectus present fairly the financial position of Aon plc and Aon plc's consolidated subsidiaries as of the dates shown and their results of operations and cash flows for the periods shown, and such financial
statements have been prepared in conformity with the generally accepted accounting principles in the United States applied on a consistent basis. The assumptions used in preparing the pro forma financial statements, if any, included in the
Registration Statement, the General Disclosure Package and the Final Prospectus provide a reasonable basis for presenting the significant effects directly attributable to the transactions or events described therein, the related pro forma
adjustments give appropriate effect to those assumptions, and the pro forma columns therein reflect the proper application of those adjustments to the corresponding historical financial statement amounts. The pro forma financial statements, if any,
included in the Registration Statement, the General Disclosure Package and the Final Prospectus comply as to form in all material respects with the applicable accounting requirements of Regulation S-X under
the Securities Act.

(u) *No Material Adverse Change in Business*. Except as disclosed in the General Disclosure Package, since the
end of the period covered by the latest audited financial statements included in the General Disclosure Package, there has been no change, nor any development or event involving a prospective change, in the financial condition, results of
operations, business, properties or prospects of the Issuers, the Guarantors, and their respective subsidiaries, taken as a whole, that is material and adverse.

(v) *Investment Company Act*. Neither the Issuers nor any of the Guarantors is and, after giving effect to the
offering and sale of the Securities and the application of the proceeds thereof as described in the General Disclosure Package, neither the Issuers nor any of the Guarantors will be, required to register as an "investment company" as
defined in the Investment Company Act of 1940, as amended (the "**Investment Company Act** ").

(w) *No Unlawful Payments.* (i) Except to the extent as would not reasonably be expected to have a
Material Adverse Effect or except as disclosed in the General Disclosure Package, the Issuers and the Guarantors are in compliance in all material respects with the United States Foreign Corrupt Practices Act of 1977 and other applicable United
States and foreign anti-corruption laws and regulations (collectively the "**Anti-Corruption Laws** "), (ii) since January 1, 2011, except to the extent as would not reasonably be expected to have a Material Adverse Effect or except
as disclosed in the General Disclosure Package, neither the Issuers nor any of the Guarantors has been notified of or, in each case, to its knowledge, investigated for a potential violation of Anti-Corruption Laws, and (iii) the Issuers, the
Guarantors and their respective subsidiaries have an operational anti-corruption compliance program that includes, at a minimum, policies, procedures and training intended to enhance awareness of and compliance by the Issuers, the Guarantors or
their respective subsidiaries with Anti-Corruption Laws.

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(x) *Compliance with Money Laundering Laws*. The operations of the Issuers, the Guarantors and their
respective subsidiaries are and have been conducted at all times and in all material respects in compliance with applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as
amended, and all applicable anti-money laundering laws, rules and regulations (collectively, the "**Anti-Money Laundering Laws** "); and neither the Issuers, any of the Guarantors nor any of their respective subsidiaries has been
notified of or, in each case, to its knowledge has been investigated for a potential violation of the Anti-Money Laundering Laws.

(y) *Compliance with OFAC*. (i) None of the Issuers, the Guarantors or any of the Guarantors'
subsidiaries or, to the knowledge of the Issuers and the Guarantors, any director, officer, employee or affiliate of the Issuers, the Guarantors or any of the Guarantors' subsidiaries is currently, or is owned or controlled by an individual or
entity ()"**Person**") that is, (A) the subject of any sanctions administered or enforced by the U.S. Department of the Treasury's Office of Foreign Assets Control, the U.S. Department of State, the United Nations Security
Council, the European Union or HM Treasury (collectively, "**Sanctions** "); or (B) organized, located or a resident in a country or territory that is currently the subject of Sanctions, including without limitation, the non-government controlled areas of the Zaporizhzhia and Kherson Regions of Ukraine, the so-called Donetsk People's Republic, the so-called Luhansk People's Republic and any other Covered Region of Ukraine identified pursuant to Executive Order 14065, the Crimea Region of Ukraine, Cuba, Iran, North Korea and Syria; and (ii) the
Issuers will not directly or, to their knowledge, indirectly use all or part of the proceeds of the offering of the Securities, or lend, contribute or otherwise make available all or part of such proceeds, to any subsidiary, joint venture partner or
other person or entity to fund or facilitate any activities or business of or with any Person, or in any country or territory, that, at the time of such funding or facilitation, is the subject of Sanctions, or in any other manner that would result
in a violation of Sanctions by any Person (including any Person participating in the offering, whether as initial purchaser, underwriter, advisor, investor or otherwise).

(z) *Taxes*. The Guarantors, the Issuers and each of the Significant Subsidiaries have filed all U.S. federal,
U.K. and material U.S. state, local and foreign tax returns required to be filed through the date of this Agreement or have requested extensions thereof; all such returns were true and complete in all material respects; all taxes shown as due and
payable on such returns have been timely paid, or withheld and remitted, to the appropriate taxing authority (except as currently being contested in good faith and for which reserves required by applicable U.S. or other generally accepted accounting
principles have been created in the financial statements of Aon plc); and no material tax deficiency has been determined adversely to the Issuers or any of the Significant Subsidiaries which has not been paid.

(aa) *Choice of Laws*. The choice of laws of the State of New York (without giving effect to its conflicts of
law principles) as the governing law of this Agreement, the Securities, the Indenture (including the Guarantees set forth therein) is a valid choice of law under the laws of England and Wales and of Ireland and will be honored by the courts of
England and Wales and of Ireland.

(bb) *Jurisdiction*. The Issuers and the Guarantors have the power to submit, and pursuant to Section 17
of this Agreement have legally, validly, effectively and irrevocably submitted, to the non-exclusive jurisdiction of Federal and state courts in the Borough of Manhattan in the City of New York; and the Co-Issuer and the Guarantors have the power to designate, appoint and empower, and pursuant to Section 17 of this Agreement, has legally, validly and effectively designated, appointed and empowered, an agent
for service of process in any suit or proceeding based on or arising under this Agreement in Federal and state courts, as applicable, in the Borough of Manhattan in the City of New York.

(cc) *eXtensible Business Reporting Language Interactive Data*. The interactive data in eXtensible Business
Reporting Language included or incorporated by reference in the Registration Statement fairly presents the required information in all material respects and has been prepared in accordance with the Commission's rules and guidelines applicable
thereto.

(dd) *Cybersecurity.* Except as to such matters as would not, singly or in the aggregate, reasonably likely
result in a Material Adverse Effect: (i) to the reasonable knowledge of the Issuers, there has been no security breach or other compromise of any of the Issuers', the Guarantors' or any of their subsidiaries' information
technology and computer systems, networks, hardware, software, data (including the data of their respective customers, employees, suppliers, vendors and any third party data maintained by or on behalf of them), equipment or technology (collectively,
" **IT Systems and Data**") and the Issuers, the Guarantors and their subsidiaries have not been notified of, and have no knowledge of any event or condition that would reasonably be expected to result in, any security breach or other
compromise to their IT Systems and Data; and (ii) the Issuers, the Guarantors and their subsidiaries are presently in compliance with all applicable laws or statutes and all judgments, orders, rules and regulations of any court or arbitrator or
governmental or regulatory authority, internal policies and contractual obligations, in each case, relating to the privacy and security of IT Systems and Data.

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3. *Purchase, Sale and Delivery of the Securities*. On the basis of the representations, warranties and
agreements and subject to the terms and conditions set forth herein, the Issuers agree to sell to the several Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Issuers at a purchase price of 99.427%
of the principal amount of the Notes plus accrued interest, if any, from February 28, 2023 to, but excluding the Closing Date (as hereinafter defined) (the "**Purchase Price** "), the principal amounts of Securities set forth
opposite the names of the Underwriters in Exhibit A hereto.

The Issuers will deliver the Securities to or as instructed by the Representatives for the accounts of the several Underwriters in a form reasonably acceptable to the Representatives against payment of the Purchase Price by the Underwriters in Federal (same day) funds by wire transfer to an account at a bank acceptable to the Representatives through the offices of Davis Polk & Wardwell LLP, 450 Lexington Avenue, New York, NY 10017, at 10:00 a.m., New York time, on February 28, 2023, or at such other time not later than seven full business days thereafter as the Representatives and the Issuers determine, such time being herein referred to as the "**Closing Date**". For purposes of Rule 15c6-1 under the Exchange Act, the Closing Date (if later than the otherwise applicable settlement date) shall be the settlement date for payment of funds and delivery of securities for all the Securities sold pursuant to the offering. The Securities so to be delivered or evidence of their issuance will be made available for inspection at the above office of Davis Polk & Wardwell LLP at least 24 hours prior to the Closing Date.

4. *Offering by Underwriters*. It is understood that the several Underwriters propose to offer the Securities
for sale to the public as set forth in the Final Prospectus.

5. *Certain Agreements of the Issuers and the Guarantors*. The Issuers and the Guarantors agree with the
several Underwriters that:

(a) *Filing of Prospectuses.* The Issuers and the Guarantors have filed or will file each Statutory Prospectus
(including the Final Prospectus) pursuant to and in accordance with Rule 424(b)(2) (or, if applicable and consented to by the Representatives, subparagraph 5) not later than the second business day following the earlier of the date it is first
used or the execution and delivery of this Agreement. The Issuers and the Guarantors have complied and will comply in all material respects with Rule 433.

(b) *Filing of Amendments; Response to Commission Requests*. The Issuers and the Guarantors will promptly
advise the Representatives of any proposal to amend or supplement the Registration Statement or any Statutory Prospectus at any time and will offer the Representatives a reasonable opportunity to comment on any such amendment or supplement; and the
Issuers and the Guarantors will also advise the Representatives promptly of (i) the filing of any such amendment or supplement, (ii) any request by the Commission or its staff for any amendment to the Registration Statement, for any
supplement to any Statutory Prospectus or for any additional information, (iii) the institution by the Commission of any stop order proceedings in respect of the Registration Statement or the threatening of any proceeding for that purpose, and
(iv) the receipt by the Issuers or any of the Guarantors of any notification with respect to the suspension of the qualification of the Securities in any jurisdiction or the institution or threatening of any proceedings for such purpose. The
Issuers and the Guarantors will use their commercially reasonable efforts to prevent the issuance of any such stop order suspending the effectiveness of the Registration Statement or the suspension of any such qualification where such lack of
qualification would have a material adverse impact on the offering of Securities contemplated hereby and, if issued, to obtain as soon as possible the withdrawal thereof.

(c) *Continued Compliance with Securities Laws*. If, at any time on or prior to the completion of the public
offer and sale of the Securities when a prospectus relating to the Securities is (or but for the exemption in Rule 172 would be) required to be delivered under the Act by any Underwriter or dealer, any event occurs as a result of which the
Final Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not
misleading, or if it is necessary at any time to amend the Registration Statement or supplement the Final Prospectus to comply with the Act, the Issuers and the Guarantors will promptly notify the Representatives of such event and will promptly
prepare and file with the Commission and furnish, at its own expense, to the Underwriters and the dealers

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and any other dealers upon request of the Representatives, an amendment or supplement which will correct such statement or omission or an amendment which will effect such compliance; provided that any such amendment or supplement required to be prepared after 90 days following the Closing Date shall be at the expense of the Underwriters. Neither the Representatives' consent to, nor the Underwriters' delivery of, any such amendment or supplement shall constitute a waiver of any of the conditions set forth in Section 7 hereof.

(d) *Rule 158.* As soon as practicable, but not later than 16 months, after the date of
this Agreement, the Issuers will make generally available to their securityholders an earnings statement covering a period of at least 12 months beginning after the date of this Agreement and satisfying the provisions of Section 11(a) of the
Act and Rule 158.

(e) *Furnishing of Prospectuses*. The Issuers and the Guarantors will furnish to the Representatives copies of
the Registration Statement, including all exhibits, any Statutory Prospectus, the Final Prospectus and all amendments and supplements to such documents, in each case as soon as available and in such quantities as the Representatives may reasonably
request during such period of time after the first date of the public offering of the Securities as is required by law to be delivered (or required to be delivered but for Rule 172 under the Act) by any Underwriter.

(f) *Blue Sky Qualifications*. The Issuers and the Guarantors will arrange for the qualification of the
Securities for sale and the determination of their eligibility for investment under the laws of such jurisdictions as the Representatives may designate and will continue such qualifications in effect so long as required for the distribution;
provided that neither an Issuer nor a Guarantor shall be required to (i) qualify as a foreign corporation or other entity or as a dealer in securities in any jurisdiction where it would not otherwise be required to so qualify, (ii) file
any general consent to service of process in any such jurisdiction or (iii) subject itself to taxation in any such jurisdiction if it is not otherwise so subject.

(g) *Reporting Requirements*. For so long as the Securities remain outstanding, the Issuers will furnish to
the Representatives and, upon request, to each of the other Underwriters, as soon as practicable after the end of each fiscal year, a copy of Aon plc's annual report to shareholders for such year; and the Issuers will furnish to the
Representatives (i) as soon as available, a copy of each report and any definitive proxy statement of Aon plc filed with the Commission under the Exchange Act or mailed to shareholders, and (ii) from time to time, such other information
concerning the Issuers or the Guarantors as the Representatives may reasonably request. However, so long as Aon plc is subject to the reporting requirements of either Section 13 or Section 15(d) of the Exchange Act and is timely filing
reports with the Commission on its Electronic Data Gathering, Analysis and Retrieval system ()"**EDGAR** "), the Issuers are not required to furnish such reports or statements to the Underwriters.

(h) *Payment of Expenses*. The Issuers and Guarantors will pay all expenses incident to the performance of
their respective obligations under this Agreement, including but not limited to expenses of printing and distributing to the Underwriters prospectuses described in Section 5(e), any fees charged by investment rating agencies for the rating of
the Securities, costs and expenses relating to investor presentations or any "road show" in connection with the offering and sale of the Securities including, without limitation, any travel expenses of the officers and employees of the
Issuers and Guarantors, and any other expenses of the Issuers or Guarantors, fees and expenses incident to listing the Securities on the New York Stock Exchange, the NYSE American, Nasdaq Stock Market and other national and foreign exchanges, fees
and expenses in connection with the registration of the Securities under the Exchange Act, and expenses incurred in distributing preliminary prospectuses and the Final Prospectus (including any amendments and supplements thereto) to the Underwriters
and for expenses incurred for preparing, printing and distributing any Issuer Free Writing Prospectuses to investors or prospective investors. It is understood, however, that, except as provided in this Agreement, the Underwriters will pay all of
their costs and expenses, including fees and expenses of counsel to the Underwriters, transfer taxes payable on resale of the Securities by them and any advertising expenses connected with any offers they make.

(i) *Use of Proceeds*. The Issuers will use the net proceeds received in connection with this offering in the
manner described in the "Use of Proceeds" section of the General Disclosure Package.

(j) *Absence of Manipulation*. The Issuers and the Guarantors will not take, directly or indirectly, any
action designed to or that would constitute or that might reasonably be expected to cause or result in, stabilization or manipulation of the price of any securities of the Issuers or Guarantors to facilitate the sale or resale of the Securities.

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(k) *Restriction on Disposition of Notes.* The Issuers and the Guarantors will not offer, sell, contract to
sell, pledge or otherwise dispose of, directly or indirectly, or file with the Commission a registration statement under the Securities Act relating to United States dollar-denominated debt securities issued or guaranteed by the Issuers or any of
the Guarantors and having a maturity of more than one year from the date of issue, or publicly disclose the intention to make any such offer, sale, pledge, disposition or filing, without the prior written consent of the Representatives for a period
beginning on the date hereof and ending on the Closing Date.

6. *Free Writing Prospectuses*. (a) *Issuer Free Writing Prospectuses*. The Issuers and the
Guarantors each represent and agree that, unless they obtain the prior consent of the Representatives, and each Underwriter represents and agrees that, unless it obtains the prior consent of the Issuers, the Guarantors and the Representatives, it
has not made and will not make any offer relating to the Securities that would constitute an Issuer Free Writing Prospectus, or that would otherwise constitute a "free writing prospectus,"<sup>
</sup>as defined in Rule 405, required to be filed with the Commission. Any such free writing prospectus consented to by the Issuers, the Guarantors and the Representatives is hereinafter referred to as a "**Permitted Free Writing Prospectus**." Each of the Issuers and the Guarantors represent that it has treated and agrees that it will treat each Permitted Free Writing Prospectus as an "issuer free writing prospectus," as defined in Rule 433,<sup></sup>and has complied and will comply in all material respects with the requirements of Rules 164 and 433 applicable to any Permitted Free Writing Prospectus, including timely Commission filing
where required, legending and record keeping.

(b) *Term Sheets*. The Issuers and Guarantors will prepare a final term sheet relating to the Securities,
containing only information that describes the final terms of the Securities and otherwise in a form consented to by the Representatives, and will file such final term sheet within the period required by Rule 433(d)(5)(ii) following the
date such final terms have been established for the offering of the Securities. Any such final term sheet is an Issuer Free Writing Prospectus and a Permitted Free Writing Prospectus for purposes of this Agreement. The Issuers and Guarantors also
consent to the use by any Underwriter of a free writing prospectus that contains only (i)(x) information describing the preliminary terms of the Securities or their offering or (y) information that describes the final terms of the Securities or
their offering and that is included in the final term sheet of the Issuers and the Guarantors contemplated in the first sentence of this subsection or (ii) other information that is not "issuer information," as defined in
Rule 433, it being understood that any such free writing prospectus referred to in clause (i) or (ii) above shall not be an Issuer Free Writing Prospectus for purposes of this Agreement.

7. *Conditions of the Obligations of the Underwriters*. The obligations of the several Underwriters to
purchase and pay for the Securities on the Closing Date will be subject to the accuracy of the representations and warranties of the Issuers and the Guarantors herein (as though made on the Closing Date), to the accuracy of the statements of the
officers of the Issuers made pursuant to the provisions hereof, to the performance by the Issuers and the Guarantors of their obligations hereunder and to the following additional conditions precedent:

(a) *Aon Accountants' Comfort Letter*. The Representatives shall have received letters, dated,
respectively, the date hereof with respect to the General Disclosure Package and the Closing Date with respect to the Final Prospectus, of Ernst & Young LLP, a registered public accounting firm and independent public accountants with
respect to Aon plc within the meaning of the Securities Laws, in form and substance satisfactory to the Representatives and containing statements and information of the type ordinarily included in accountants' comfort letters with respect to
the financial statements and certain financial information contained or incorporated by reference in the General Disclosure Package and the Final Prospectus, and the specified date of such letters shall be a date no more than three business days
prior to the date hereof or the Closing Date, as applicable.

(b) *Filing of Prospectus.* The Final Prospectus shall have been filed with the Commission in accordance with
the Rules and Regulations and Section 5(a) hereof. No stop order suspending the effectiveness of the Registration Statement or of any part thereof shall have been issued and no proceedings for that purpose shall have been instituted or, to the
knowledge of the Issuers, the Guarantors or any Underwriter, shall be contemplated by the Commission.

(c) *No Material Adverse Change*. Subsequent to the execution and delivery of this Agreement, there shall not
have occurred (i) any change, or any development or event involving a prospective change, in the financial condition, results of operations, business or properties of the Issuers, the Guarantors and their respective subsidiaries taken as a
whole, which, in the judgment of the Representatives, is material and adverse and makes it impractical or inadvisable to market the Securities; (ii) any downgrading in the rating of any debt securities or preferred stock of the Issuers or

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any of the Guarantors by any "nationally recognized statistical rating organization" (as defined in Section 3(a)(62) of the Exchange Act), or any public announcement that any such organization has under surveillance or review its rating of any debt securities or preferred stock of the Issuers or any of the Guarantors for a possible downgrading of such rating or any announcement that the Issuers or any of the Guarantors has been placed on negative outlook; (iii) any change in U.S. or international financial, political or economic conditions or currency exchange rates or exchange controls the effect of which is such as to make it, in the judgment of the Representatives, impracticable to market or to enforce contracts for the sale of the Securities, whether in the primary market or in respect of dealings in the secondary market; (iv) any suspension or material limitation of trading in securities generally on the New York Stock Exchange, or any setting of minimum or maximum prices for trading on such exchange; (v) any suspension of trading of any securities of the Issuers or any of the Guarantors on any exchange or in the over-the-counter market; (vi) any banking moratorium declared by any U.S. federal or New York authorities; (vii) any major disruption of settlements of securities, payment, or clearance services in the United States or any other country where such securities are listed; or (viii) any attack on, outbreak or escalation of hostilities or act of terrorism involving the United States, any declaration of war by Congress or any other national or international calamity or emergency if, in the judgment of the Representatives, the effect of any such attack, outbreak, escalation, act, declaration, calamity or emergency is such as to make it impractical or inadvisable to market the Securities or to enforce contracts for the sale of the Securities.

(d) *Opinion of In-House Counsel to the Issuers*. The Representatives
shall have received an opinion, dated the Closing Date, of the In-House Counsel to the Issuers, in form and substance reasonably satisfactory to the Representatives, to the effect set forth in Exhibit D
hereto.

(e) *Opinion of Special U.K. Counsel for the Co-Issuer and AGL, Opinion of Special U.S. Counsel for the Issuers and the Guarantors and Opinion of Special Irish Counsel for Aon plc*. The Representatives shall have received an opinion, dated the Closing Date, of Freshfields Bruckhaus Deringer LLP, special U.K. counsel
to the Co-Issuer and AGL, an opinion dated the Closing Date, of Sidley Austin LLP, special U.S. counsel to the Issuers and the Guarantors and an opinion, dated the Closing Date, of Matheson, special Irish
counsel to Aon plc, in form and substance reasonably satisfactory to the Representatives, to the effect set forth in Exhibit E hereto.

(f) *Opinion and Disclosure Letter of Counsel for Underwriters.* The Representatives shall have received from
Davis Polk & Wardwell LLP, counsel for the Underwriters, an opinion and a disclosure letter, dated the Closing Date, with respect to such matters as the Representatives may reasonably require, and the Issuers shall have furnished to such
counsel such documents as they request for the purpose of enabling them to pass upon such matters.

(g) *Officer's Certificate*. The Representatives shall have received a certificate, dated the Closing
Date, of an executive officer of the Issuers and the Guarantors and a principal financial or accounting officer or treasurer of the Issuers and the Guarantors in which such officers shall state that: the representations and warranties of the Issuers
and the Guarantors in clauses (a), (c), (d), (e), (f), (j), (k), (m), (p), (v) and (y) of Section 2 of this Agreement are true and correct in all material respects; the representations and warranties of the Issuers and the Guarantors in
clauses (b), (g), (h), (i), (l), (n), (o), (q), (r), (s), (t), (u), (w), (x), (z), (aa), (bb), (cc) and (dd) of Section 2 of this Agreement are true and correct; the Issuers and the Guarantors have complied in all material respects with all
agreements and satisfied all conditions on its part to be performed or satisfied hereunder at or prior to the Closing Date; no stop order suspending the effectiveness of the Registration Statement has been issued and no proceedings for that purpose
have been instituted or, to the best of their knowledge and after reasonable investigation, are contemplated by the Commission; and, subsequent to the dates of the most recent financial statements in the General Disclosure Package, there has been no
material adverse change, nor any development or event involving a prospective material adverse change, in the financial condition, results of operations, business or properties of the Issuers, Guarantors and their respective subsidiaries taken as a
whole except as set forth in the General Disclosure Package or as described in such certificate.

The Issuers and the Guarantors will furnish the Representatives with such conformed copies of such opinions, certificates, letters and documents as the Representatives may reasonably request. The Representatives may in their sole discretion waive on behalf of the Underwriters compliance with any conditions to the obligations of the Underwriters hereunder.

8. *Indemnification and Contribution*. (a) *Indemnification of Underwriters*. The Issuers and the
Guarantors will jointly and severally indemnify and hold harmless each Underwriter, its partners, members, directors, officers, employees, agents, affiliates and each person, if any, who controls such Underwriter within the meaning of
Section 15 of the Act

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or Section 20 of the Exchange Act (each, an "**Indemnified Party**"), against any and all losses, claims, damages or liabilities, joint or several, to which such Indemnified Party may become subject, under the Securities Act, the Exchange Act, other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of any material fact contained in any part of the Registration Statement at any time, any Statutory Prospectus as of any time, the Final Prospectus or any Issuer Free Writing Prospectus, or arise out of or are based upon the omission or alleged omission of a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading, and will reimburse each Indemnified Party for any legal or other expenses reasonably incurred by such Indemnified Party in connection with investigating or defending against any loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such Indemnified Party is a party thereto), whether threatened or commenced, and in connection with the enforcement of this provision with respect to any of the above as such expenses are incurred; provided, however, that the Issuers and the Guarantors will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement in or omission or alleged omission from (i) that part of the Registration Statement that constitutes the Form T-1 of the Trustee under the Trust Indenture Act and (ii) any of such documents in reliance upon and in conformity with written information furnished to the Issuers by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in subsection (b) below.

(b) *Indemnification of Issuers and Guarantors*. Each Underwriter will severally and not jointly indemnify and
hold harmless each of the Issuers, the Guarantors, each of their respective directors and each of their respective officers who signs a Registration Statement and each person, if any, who controls any Issuer or any Guarantor within the meaning of
Section 15 of the Securities Act or Section 20 of the Exchange Act (each, an "**Underwriter Indemnified Party** "), against any losses, claims, damages or liabilities to which such Underwriter Indemnified Party may become
subject, under the Act, the Exchange Act, other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or
alleged untrue statement of any material fact contained in any part of the Registration Statement at any time, any Statutory Prospectus as of any time, the Final Prospectus, or any Issuer Free Writing Prospectus, or arise out of or are based upon
the omission or the alleged omission of a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue
statement or omission or alleged omission was made in reliance upon and in conformity with written information furnished to the Issuers by such Underwriter through the Representatives specifically for use therein, and will reimburse any legal or
other expenses reasonably incurred by such Underwriter Indemnified Party in connection with investigating or defending against any such loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such
Underwriter Indemnified Party is a party thereto), whether threatened or commenced, based upon any such untrue statement or omission, or any such alleged untrue statement or omission as such expenses are incurred, it being understood and agreed that
the only such information furnished by any Underwriter through the Representatives consists of the following information in the General Disclosure Package and the Final Prospectus furnished on behalf of each Underwriter: the concession and
reallowance figures appearing in the third paragraph under the caption "Underwriting"; the statement of market making with respect to the Underwriters in the third sentence of the fifth paragraph under the caption "Underwriting";
and the description of stabilizing transactions, over-allotment transactions, syndicate covering transactions and penalty bids appearing in the ninth paragraph under the caption "Underwriting."

(c) *Actions against Parties; Notification*. Promptly after receipt by an indemnified party under this Section
of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against the indemnifying party under subsection (a) or (b) above, notify the indemnifying party of the commencement thereof;
but the failure to notify the indemnifying party shall not relieve it from any liability that it may have under subsection (a) or (b) above except to the extent that it has been materially prejudiced (through the forfeiture of substantive
rights or defenses) by such failure; and provided further that the failure to notify the indemnifying party shall not relieve it from any liability that it may have to an indemnified party otherwise than under subsection (a) or (b) or above. In
case any such action is brought against any indemnified party and it notifies the indemnifying party of the commencement thereof, the indemnifying party will be entitled to participate therein and, to the extent that it may wish, jointly with any
other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be counsel to

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the indemnifying party in such action), and after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the indemnifying party will not be liable to such indemnified party under this Section for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense thereof other than reasonable costs of investigation. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened action in respect of which any indemnified party is or could have been a party and indemnity could have been sought hereunder by such indemnified party unless such settlement (i) includes an unconditional release of such indemnified party from all liability on any claims that are the subject matter of such action and (ii) does not include a statement as to, or an admission of, fault, culpability or a failure to act by or on behalf of any indemnified party.

(d) *Contribution*. If the indemnification provided for in this Section is unavailable or insufficient to hold
harmless an indemnified party under subsection (a) or (b) above, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of the losses, claims, damages or liabilities referred to in
subsection (a) or (b) above (i) in such proportion as is appropriate to reflect the relative benefits received by the Issuers and the Guarantors on the one hand and the Underwriters on the other hand from the offering of the Securities or
(ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the
Issuers and the Guarantors on the one hand and the Underwriters on the other hand in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities as well as any other relevant equitable considerations.
The relative benefits received by the Issuers and the Guarantors on the one hand and the Underwriters on the other hand shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by
the Issuers bear to the total underwriting discounts and commissions received by the Underwriters. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the
omission or alleged omission to state a material fact relates to information supplied by the Issuers and the Guarantors or the Underwriters and the parties' relative intent, knowledge, access to information and opportunity to correct or prevent
such untrue statement or omission. The amount paid by an indemnified party as a result of the losses, claims, damages or liabilities referred to in the first sentence of this subsection (d) shall be deemed to include any legal or other expenses
reasonably incurred by such indemnified party in connection with investigating or defending any action or claim which is the subject of this subsection (d). Notwithstanding the provisions of this subsection (d), no Underwriter shall be required to
contribute any amount in excess of the amount by which the total price at which the Notes underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been
required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any
person who was not guilty of such fraudulent misrepresentation. The Underwriters' obligations in this subsection (d) to contribute are several in proportion to their respective underwriting obligations and not joint. The Issuers, the
Guarantors and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 8(d) were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any
other method of allocation which does not take account of the equitable considerations referred to in this Section 8(d).

9. *Default of Underwriters*. If any Underwriter or Underwriters default in their obligations to purchase the
Securities hereunder on the Closing Date and the aggregate principal amount of the Securities that such defaulting Underwriter or Underwriters agreed but failed to purchase does not exceed 10% of the total principal amount of the Securities that the
Underwriters are obligated to purchase on the Closing Date, the Representatives may make arrangements satisfactory to the Issuers for the purchase of the Securities by other persons, including any of the Underwriters, but if no such arrangements are
made by the Closing Date, the non-defaulting Underwriters shall be obligated severally, in proportion to their respective commitments hereunder, to purchase the Securities that such defaulting Underwriters
agreed but failed to purchase on the Closing Date. If any Underwriter or Underwriters so default and the aggregate principal amount of the Securities with respect to which such default or defaults occur exceeds 10% of the total principal amount of
the Securities that the Underwriters are obligated to purchase on the Closing Date and arrangements satisfactory to the Representatives and the Issuers for the purchase of the Securities by other persons are not made within 36 hours after such
default, this Agreement will terminate without liability on the part of any non-defaulting Underwriter or the Issuers, except as provided in Section 10. As used in this Agreement, the term
"Underwriter" includes any person substituted for an Underwriter under this Section. Nothing herein will relieve a defaulting Underwriter from liability for its default.

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10. *Survival of Certain Representations and Obligations*. The respective indemnities, agreements,
representations, warranties and other statements of the Issuers, the Guarantors or their officers and of the several Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation,
or statement as to the results thereof, made by or on behalf of any Underwriter, the Issuers, the Guarantors or any of their respective representatives, officers or directors or any controlling person, and will survive delivery of and payment for
the Securities. If the purchase of the Securities by the Underwriters is not consummated for any reason other than solely because of the termination of this Agreement pursuant to Sections 7(c)(iii), 7(c)(iv), 7(c)(vi), 7(c)(vii), 7(c)(viii)
and 9 hereof, the Issuers and the Guarantors will reimburse the Underwriters for all out-of-pocket expenses reasonably incurred by them in connection with the
offering of the Securities, and the respective obligations of the Issuers, the Guarantors and the Underwriters pursuant to Section 8 hereof shall remain in effect. In addition, if any Securities have been purchased hereunder, the
representations and warranties in Section 2 and all obligations under Section 5 shall also remain in effect.

11. *Notices*. All communications hereunder will be in writing and, if sent to the Underwriters, will be
mailed, delivered or telegraphed and confirmed:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to the Representatives at: Morgan Stanley & Co. LLC, 1585 Broadway, 29th Floor, New York, New York
10036, Attention: Investment Banking Division (fax: (212) 507-8999); BofA Securities, Inc., 1540 Broadway, New York, New York 10036, Attention: High Grade Debt Capital Markets Transaction Management/Legal
(fax: (646) 855 5958); and HSBC Securities (USA) Inc., 452 Fifth Avenue, New York, New York 10018, Attention: Transaction Management Group; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to the Issuers at Aon Corporation, 200 E. Randolph Street, Chicago, Illinois 60601, Attention: General Counsel;

*provided*, however, that any notice to an Underwriter pursuant to Section 8 will be mailed, delivered or telegraphed and confirmed to such Underwriter.

12. *Successors*. This Agreement will inure to the benefit of and be binding upon the parties hereto and their
respective successors and the officers and directors and controlling persons referred to in Section 8, and no other person will have any right or obligation hereunder.

13. *Representation of Underwriters*. The Representatives will act for the several Underwriters in connection
with this financing, and any action under this Agreement taken by the Representatives jointly will be binding upon all the Underwriters.

14. *Counterparts*. This Agreement may be executed in any number of counterparts, each of which shall be
deemed to be an original, but all such counterparts shall together constitute one and the same Agreement. The words "execution," "signed," "signature," and words of like import in this Agreement or in any other
certificate, agreement or document related to this Agreement, if any, shall include images of manually executed signatures transmitted by facsimile or other electronic format (including, without limitation, "pdf", "tif" or
"jpg") and other electronic signatures (including, without limitation, DocuSign and AdobeSign). The use of electronic signatures and electronic records (including, without limitation, any contract or other record created, generated, sent,
communicated, received, or stored by electronic means) shall be of the same legal effect, validity and enforceability as a manually executed signature or use of a paper-based record-keeping system to the fullest extent permitted by applicable law,
including the Federal Electronic Signatures in Global and National Commerce Act, the New York State Electronic Signatures and Records Act and any other applicable law, including, without limitation, any state law based on the Uniform Electronic
Transactions Act or the Uniform Commercial Code.

15. *Headings*. The headings herein are included for convenience of reference only and are not intended to be
part of, or to affect the meaning or interpretation of this Agreement.

16. *Absence of Fiduciary Relationship.* The Issuers and the Guarantors acknowledge and agree that:

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(a) *No Other Relationship*. The Representatives have been retained solely to act as underwriters in
connection with the sale of the Securities and that no fiduciary, advisory or agency relationship between the Issuers, on the one hand, and the Representatives, on the other, has been created in respect of any of the transactions contemplated by
this Agreement or the Final Prospectus, irrespective of whether the Representatives have advised or are advising the Issuers or any of the Guarantors on other matters;

(b) *Arms' Length Negotiations*. The price of the Securities set forth in this Agreement was established
by the Issuers and the Guarantors following discussions and arms-length negotiations with the Representatives, and the Issuers and the Guarantors are capable of evaluating and understanding and understand and accept the terms, risks and conditions
of the transactions contemplated by this Agreement;

(c) *Absence of Obligation to Disclose*. The Issuers and the Guarantors have been advised that the
Representatives and their affiliates are engaged in a broad range of transactions which may involve interests that differ from those of the Issuers or any of the Guarantors and that the Representatives have no obligation to disclose such interests
and transactions to the Issuers or any of the Guarantors by virtue of any fiduciary, advisory or agency relationship; and

(d) *Waiver*. The Issuers and the Guarantors waive, to the fullest extent permitted by law, any claims either
of the Issuers or any of the Guarantors may have against the Representatives for breach of fiduciary duty or alleged breach of fiduciary duty and agree that the Representatives shall have no liability (whether direct or indirect) to the Issuers or
any of the Guarantors in respect of such a fiduciary duty claim or to any person asserting a fiduciary duty claim on behalf of or in right of the Issuers, including members, stockholders, employees or creditors of the Issuers or any of the
Guarantors.

17. *Applicable Law*. (a) This Agreement and any claim, controversy or dispute arising
under or related to this Agreement shall be governed by, and construed in accordance with, the laws of the State of New York, without giving effect to its conflicts of law principles.

(b) *Waiver of Jury Trial.* Each of the parties hereto hereby waives any right to trial by jury in any suit or
proceeding arising out of or relating to this Agreement.

(c) *Submission to Jurisdiction*. The Issuers and the Guarantors hereby submit to the non-exclusive jurisdiction of the federal and state courts in the Borough of Manhattan in the City of New York in any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated
hereby. The Issuers and the Guarantors irrevocably and unconditionally waive any objection to the laying of venue of any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated hereby in federal and state
courts in the Borough of Manhattan in the City of New York and irrevocably and unconditionally waive and agree not to plead or claim in any such court that any such suit or proceeding in any such court has been brought in an inconvenient forum. The
Guarantors and the Co-Issuer hereby irrevocably appoint the Company with an office at 200 E. Randolph Street, Chicago, Illinois 60601, Attention: General Counsel, as their agent to receive on behalf of the
Guarantors service of any legal process which may be served in all such actions and proceedings. Such service may be made by mail or delivery of such process to the Co-Issuer and the Guarantors in care of such
agent at the agent's address set forth above and the Co-Issuer and the Guarantors hereby irrevocably authorize and direct such agent to accept such service on behalf of the Co-Issuer and the Guarantors.

18. Recognition of the U.S. Special Resolution Regimes.

(a) In the event that any Underwriter that is a Covered Entity becomes subject to a proceeding under a U.S. Special
Resolution Regime, the transfer from such Underwriter of this Agreement, and any interest and obligation in or under this Agreement, will be effective to the same extent as the transfer would be effective under the U.S. Special Resolution Regime if
this Agreement, and any such interest and obligation, were governed by the laws of the United States or a state of the United States.

(b) In the event that any Underwriter that is a Covered Entity or a BHC Act Affiliate of such Underwriter becomes
subject to a proceeding under a U.S. Special Resolution Regime, Default Rights under this Agreement that may be exercised against such Underwriter are permitted to be exercised to no greater extent than such Default Rights could be exercised under
the U.S. Special Resolution Regime if this Agreement were governed by the laws of the United States or a state of the United States.

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"**BHC Act Affiliate**" has the meaning assigned to the term "affiliate" in, and shall be interpreted in accordance with, 12 U.S.C. § 1841(k).

"**Covered Entity**" means any of the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) a "covered entity" as that term is defined in, and interpreted in accordance with, 12 C.F.R. §
252.82(b);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(ii) a "covered bank" as that term is defined in, and interpreted in accordance with, 12 C.F.R. §
47.3(b); or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(iii) a "covered FSI" as that term is defined in, and interpreted in accordance with, 12 C.F.R. §
382.2(b).

"**Default Right**" has the meaning assigned to that term in, and shall be interpreted in accordance with, 12 C.F.R. §§ 252.81, 47.2 or 382.1, as applicable.

"**U.S. Special Resolution Regime**" means each of (i) the Federal Deposit Insurance Act and the regulations promulgated thereunder and (ii) Title II of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the regulations promulgated thereunder.

19. *Compliance with USA PATRIOT Act*. In accordance with the requirements of the USA PATRIOT Act (Title III
of Pub. L. 107-56 (signed into law October 26, 2001)), the Underwriters are required to obtain, verify and record information that identifies their respective clients, including the Issuer, which
information may include the name and address of their respective clients, as well as other information that will allow the Underwriters to properly identify their respective clients.

*[Signature Pages As Follows]*

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If the foregoing is in accordance with the Representatives' understanding of our agreement, kindly sign and return to us your counterpart hereof, whereupon it will become a binding agreement among the Issuers, the Guarantors and the several Underwriters in accordance with its terms.

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| | |
|:---|:---|
| Very truly yours, | Very truly yours, |
| AON CORPORATION | AON CORPORATION |
| By: | /s/ Julie Cho |
|  | Name: Julie Cho |
|  | Title: Vice President and Secretary |
| AON GLOBAL HOLDINGS PLC | AON GLOBAL HOLDINGS PLC |
| By: | /s/ Gardner Mugashu |
|  | Name: Gardner Mugashu |
|  | Title: Director |
| AON PLC | AON PLC |
| By: | /s/ Paul Hagy |
|  | Name: Paul Hagy |
|  | Title: Treasurer |
| AON GLOBAL LIMITED | AON GLOBAL LIMITED |
| By: | /s/ Alistair Boyd |
|  | Name: Alistair Boyd |
|  | Title: Director |

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[*Signature Page to Underwriting Agreement*]

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*The foregoing Underwriting Agreement is hereby confirmed and accepted as of the date first above written.* 

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| | |
|:---|:---|
| Acting on behalf of itself and as a | Acting on behalf of itself and as a |
| Representative of the several Underwriters | Representative of the several Underwriters |
| By: Morgan Stanley & Co. LLC | By: Morgan Stanley & Co. LLC |
| By: | /s/ Victoria Franco |
|  | Name: Victoria Franco |
|  | Title: Vice President |

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[*Signature Page to Underwriting Agreement*]

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*The foregoing Underwriting Agreement is hereby confirmed and accepted as of the date first above written.* 

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| | |
|:---|:---|
| Acting on behalf of itself and as a | Acting on behalf of itself and as a |
| Representative of the several Underwriters | Representative of the several Underwriters |
| By: BofA Securities, Inc. | By: BofA Securities, Inc. |
| By: | /s/ Randolph Randolph |
|  | Name: Randolph Randolph |
|  | Title: Managing Director |

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[*Signature Page to Underwriting Agreement*]

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*The foregoing Underwriting Agreement is hereby confirmed and accepted as of the date first above written.* 

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| | |
|:---|:---|
| Acting on behalf of itself and as a | Acting on behalf of itself and as a |
| Representative of the several Underwriters | Representative of the several Underwriters |
| By: HSBC Securities (USA) Inc. | By: HSBC Securities (USA) Inc. |
| By: | /s/ Patrice Altongy |
|  | Name: Patrice Altongy |
|  | Title: Managing Director |

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[*Signature Page to Underwriting Agreement*]

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**EXHIBIT A** 

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| | |
|:---|:---|
| **Underwriter** | **Principal Amount of the**<br>**Notes** |
|  Morgan Stanley & Co. LLC | $212500000 |
|  BofA Securities, Inc. | $212500000 |
|  HSBC Securities (USA) Inc. | $212500000 |
|  ANZ Securities, Inc. | $18750000 |
|  Aon Securities LLC | $18750000 |
|  nabSecurities, LLC | $18750000 |
| R. Seelaus & Co., LLC | $18750000 |
|  Scotia Capital (USA) Inc. | $18750000 |
|  Wells Fargo Securities, LLC | $18750000 |
|  **Total:** | $**750000000** |

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Exhibit A-1

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**EXHIBIT B** 

**1.** **General Use Free Writing Prospectus (included in the General Disclosure Package)** 

"General Use Issuer Free Writing Prospectus" means:

The pricing term sheet, dated February 23, 2023, a copy of which is attached hereto as Annex B-1.

**2.** **Other Information Included in the General Disclosure Package** 

The following information is also included in the General Disclosure Package:

None

Exhibit B-1

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**ANNEX B-1** 

Exhibit B-1-1

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Exhibit B-1-2

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Exhibit B-1-3

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**EXHIBIT C** 

**Significant Subsidiaries** 

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| | |
|:---|:---|
| **Significant subsidiary:** | **Jurisdiction of incorporation:** |
| Aon Global Holdings plc | United Kingdom |
| Aon Corporation | Delaware |
| Aon Global Limited | United Kingdom |
| Randolph Finance Unlimited Company | Ireland |
| Aon Group, Inc. | Maryland |
| Aon International Holdings, Inc. | Maryland |
| Aon Group International N.V. | Netherlands |
| Aon Holdings International B.V. | Netherlands |
| Aon Holdings B.V. | Netherlands |
| Aon Southern Europe B.V. | Netherlands |
| Aon UK Group Limited | United Kingdom |
| Aon UK Holdings Intermediaries Limited | United Kingdom |
| Aon UK Holdings Limited | United Kingdom |
| Aon UK Limited | United Kingdom |
| Aon Risk Services Companies, Inc. | Maryland |
| Aon Finance N.S. 1, ULC | Nova Scotia |
| Aon Risk Services, Inc. of Maryland | Maryland |
| Aon Consulting, Inc. | New Jersey |
| Aon North America Inc. | Delaware |
| Aon Global Holdings Intermediaries Limited | United Kingdom |

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Exhibit C-1

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**EXHIBIT D** 

**Opinion of In-House Counsel to the Issuers and the Guarantors** 

Exhibit D-1

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**EXHIBIT E** 

**Opinion of Freshfields Bruckhaus Deringer LLP** 

Exhibit E-1

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**EXHIBIT F** 

**Opinion of Sidley Austin LLP** 

Exhibit F-1

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**EXHIBIT G** 

**Opinion of Matheson** 

Exhibit G-1

## Exhibit 4.2

**Exhibit 4.2** 

**AON CORPORATION** 

**AON GLOBAL HOLDINGS PLC** 

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**FIFTH INDENTURE SUPPLEMENT** 

**DATED AS OF FEBRUARY 28, 2023** 

**TO** 

**THE AMENDED AND RESTATED INDENTURE** 

**DATED AS OF APRIL 1, 2020** 

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**THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A.** 

**TRUSTEE** 

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**DEBT SECURITIES** 

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THIS FIFTH INDENTURE SUPPLEMENT (the "<u>Fifth Indenture Supplement</u>"), is dated as of February 28, 2023, among Aon Corporation, a corporation duly organized and existing under the laws of the State of Delaware (hereinafter sometimes called the "<u>Company</u>", which term includes any successor Person under the Indenture hereinafter referred to), Aon Global Holdings plc, a public limited company duly organized and existing under the laws of England and Wales (hereinafter sometimes called "<u>AGH</u>" or the "<u>Co-Issuer</u>", which term includes any successor Person under the Indenture hereinafter referred to, and, together with the Company, the "<u>Issuers</u>"), Aon plc, a public limited company duly organized and existing under the laws of Ireland (hereinafter sometimes called "<u>Aon Ireland</u>"), Aon Global Limited, a private limited company duly organized and existing under the laws of England and Wales and prior to its re-registration, a public limited company formed under the laws of England and Wales named Aon plc (hereinafter sometimes called the "<u>Aon UK</u>" and, together with Aon Ireland, the "<u>Guarantors</u>" and each, a "<u>Guarantor</u>"), and The Bank of New York Mellon Trust Company, N.A., a national banking association duly incorporated and existing under the laws of the United States of America (hereinafter sometimes called the "<u>Trustee</u>", which term shall include any successor trustee appointed pursuant to Article Seven of the Base Indenture), and is a supplemental indenture amending and restating the Base Indenture (as defined below).

**WITNESSETH:** 

WHEREAS, the Company, AGH, the Guarantors and the Trustee executed and delivered an Amended and Restated Indenture, dated as of April 1, 2020 (the "<u>Base Indenture</u>" and together with this Fifth Indenture Supplement, the "<u>Indenture</u>"), to provide for the issuance from time to time for its lawful purposes debt securities (hereinafter called "<u>Securities</u>" or, in the singular, "<u>Security</u>") evidencing its unsecured indebtedness.

WHEREAS, Section 10.01 of the Base Indenture provides that a supplemental indenture may be entered into by the Company, AGH, Aon Ireland and Aon UK when authorized by or pursuant to a Board Resolution, and the Trustee without the consent of any Holders to make provisions to establish the form or terms of Securities of any series as permitted by Sections 2.01 and 2.03 of the Base Indenture.

WHEREAS, solely with respect to the application of such provisions to the Offered Securities, the Company, the Co-Issuer and the Guarantors, desire to (i) effect that the Issuers co-issue the Notes, (ii) effect such guarantee by Aon Ireland and Aon UK, (iii) establish the form and terms of the Notes without the consent of any Holders as permitted by Sections 2.01 and 2.03 of the Base Indenture and (iv) execute a supplemental indenture to the Base Indenture pursuant to Section 10.01 thereof by amending and restating herein the Base Indenture in relevant part.

WHEREAS, each of the Company, the Co-Issuer, Aon Ireland and Aon UK represents that all acts and things necessary to present a valid and binding supplemental indenture and agreement according to its terms have been done and performed, and the execution of this Indenture as a supplemental indenture to the Base Indenture by each of the Company, the Co-Issuer, Aon Ireland and Aon UK has in all respects been duly authorized, and each of the Company, the Co-Issuer, Aon Ireland and Aon UK, in the exercise of legal rights and power in it vested, is executing this Indenture.

NOW, THEREFORE, for and in consideration of the foregoing premises, the Issuers, the Guarantors and the Trustee mutually covenant and agree for the equal and proportionate benefit of the respective Holders from time to time of the Notes as follows:

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ARTICLE I

DEFINED TERMS

SECTION 1.01. <u>Defined Terms</u>. Except as otherwise expressly provided in this Fifth Indenture Supplement or in the respective form of Note attached as <u>Exhibit A</u> hereto or otherwise clearly required by the context hereof or thereof, all capitalized terms used and not defined in this Fifth Indenture Supplement that are defined in the Base Indenture shall have the meanings assigned to them in the Base Indenture. For all purposes of this Fifth Indenture Supplement only:

"<u>Base Indenture</u>" has the meaning set forth in the recitals hereof.

"<u>Board of Directors</u>", with respect to the Issuers, shall mean the board of directors (or comparable governing body) of each such Issuer, the executive committee of each such Issuer or any other committee duly authorized to exercise the powers and authority of the board of directors (or comparable governing body) of each such Issuer with respect to this Indenture.

"<u>Closing Date</u>" means February 28, 2023.

"<u>Co-Issuer</u>" means the Person named as the "Co-Issuer" set forth in the preamble hereof, until a successor Person shall have become such pursuant to the applicable provisions of this Indenture, and thereafter "Co-Issuer" shall mean such successor Person.

"<u>Company</u>" (i) with respect to the provisions set out in the Fifth Indenture Supplement, has the meaning set forth in the preamble hereof, until a successor Person shall have become such pursuant to the applicable provisions of the Indenture, and thereafter "Company" shall mean such successor Person and (ii) with respect to the Base Indenture and only in the context where the Fifth Indenture Supplement has not expressly amended and restated a provision of the Base Indenture, the term "Company" shall mean (a) the Person named as the "Company" in the first paragraph of the Base Indenture until a successor Person shall have become such pursuant to the applicable provisions of this Indenture, and thereafter "Company" shall mean such successor Person and (b) the Person named as the "AGH" in the first paragraph of the Base Indenture, acting in its capacity as a co-issuer in accordance with this Fifth Indenture Supplement, until a successor Person shall have become such pursuant to the applicable provisions of this Indenture, and thereafter "Company" shall include such successor Person.

"<u>Global Securities Legend</u>" means the legend set forth on the form of Note attached as <u>Exhibit A</u> hereto.

"<u>Guarantors</u>" has the meaning set forth in the recitals hereof.

"<u>Indenture</u>" has the meaning set forth in the recitals hereof.

"<u>Interest Payment Date</u>" has the meaning set forth in Section 2.02 hereof.

"<u>Notes</u>" means a new series of Securities to be co-issued by the Company and the Co-Issuer to be known as $750,000,000 aggregate principal amount of 5.350% senior notes due 2033 (the "<u>Notes,</u>" substantially in the form attached hereto as <u>Exhibit A</u>), fully and unconditionally guaranteed as to payment of principal and interest by Aon Ireland and Aon UK, such series designated in Section 2.01 hereof that are authenticated and delivered under the Indenture. For all purposes of this Fifth Indenture Supplement, the term "Notes" shall include the Notes initially issued on the Closing Date and any other Notes of such series issued after the Closing Date. For purposes of the Indenture, the Notes shall constitute a single series of Securities under the Indenture and shall vote together to the extent so provided in the Indenture.

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"<u>Original Indenture</u>" has the meaning set forth in the recitals hereof.

"<u>Par Call Date</u>" means November 28, 2032 (the date that is three months prior to the Stated Maturity for the Notes).

"<u>Regular Record Date</u>" has the meaning set forth in Section 2.02 hereof.

"<u>Stated Maturity</u>" has the meaning set forth in Section 2.02 hereof.

"<u>Treasury Rate</u>" means, with respect to any redemption date, the yield determined by the Issuers in accordance with the following two paragraphs:

The Treasury Rate shall be determined by the Issuers after 4:15 p.m., New York City time (or after such time as yields on U.S. government securities are posted daily by the Board of Governors of the Federal Reserve System), on the third business day preceding the redemption date based upon the yield or yields for the most recent day that appear after such time on such day in the most recent statistical release published by the Board of Governors of the Federal Reserve System designated as "Selected Interest Rates (Daily)—H.15" (or any successor designation or publication) ("<u>H.15</u>") under the caption "U.S. government securities–Treasury constant maturities–Nominal" (or any successor caption or heading). In determining the Treasury Rate, the Issuers shall select, as applicable: (1) the yield for the Treasury constant maturity on H.15 exactly equal to the period from the redemption date to the Par Call Date (the "<u>Remaining Life</u>"); or (2) if there is no such Treasury constant maturity on H.15 exactly equal to the Remaining Life, the two yields – one yield corresponding to the Treasury constant maturity on H.15 immediately shorter than and one yield corresponding to the Treasury constant maturity on H.15 immediately longer than the Remaining Life – and shall interpolate to the Par Call Date on a straight-line basis (using the actual number of days) using such yields and rounding the result to three decimal places; or (3) if there is no such Treasury constant maturity on H.15 shorter than or longer than the Remaining Life, the yield for the single Treasury constant maturity on H.15 closest to the Remaining Life. For purposes of this paragraph, the applicable Treasury constant maturity or maturities on H.15 shall be deemed to have a maturity date equal to the relevant number of months or years, as applicable, of such Treasury constant maturity from the redemption date.

If on the third business day preceding the redemption date H.15 is no longer published, the Issuers shall calculate the Treasury Rate based on the rate per annum equal to the semi-annual equivalent yield to maturity at 11:00 a.m., New York City time, on the second business day preceding such redemption date of the United States Treasury security maturing on, or with a maturity that is closest to, the Par Call Date, as applicable. If there is no United States Treasury security maturing on the Par Call Date but there are two or more United States Treasury securities with a maturity date equally distant from the Par Call Date, one with a maturity date preceding the Par Call Date and one with a maturity date following the Par Call Date, the Issuers shall select the United States Treasury security with a maturity date preceding the Par Call Date. If there are two or more United States Treasury securities maturing on the Par Call Date or two or more United States Treasury securities meeting the criteria of the preceding sentence, the Issuers shall select from among these two or more United States Treasury securities the United States Treasury security that is trading closest to par based upon the average of the bid and asked prices for such United States Treasury securities at 11:00 a.m.,

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New York City time. In determining the Treasury Rate in accordance with the terms of this paragraph, the semi-annual yield to maturity of the applicable United States Treasury security shall be based upon the average of the bid and asked prices (expressed as a percentage of principal amount) at 11:00 a.m., New York City time, of such United States Treasury security, and rounded to three decimal places.

"<u>Trustee</u>" has the meaning set forth in the preamble hereof.

The parties hereto acknowledge that certain terms are defined in both the Base Indenture and in this Fifth Indenture Supplement. The parties hereto hereby agree that, unless otherwise expressly stated or the context otherwise requires, any term which is defined in either the Base Indenture or this Fifth Indenture Supplement, when used with respect to or in the respective certificates evidencing the Notes, shall have the meaning set forth in this Fifth Indenture Supplement.

ARTICLE II

TERMS OF THE NOTES

SECTION 2.01. <u>Establishment of the Notes</u>.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) There is hereby authorized and established a series of Securities designated the 5.350% senior notes due 2033, limited in aggregate principal amount to $750,000,000(except for Notes authenticated and delivered upon registration of transfer of, or in exchange for, or in lieu of, other Notes pursuant to Sections 2.05, 2.06, 2.07, 3.03, 6.01 or 10.04 of the Indenture); provided that the Issuers may, from time to time, without notice to or consent of Holders or beneficial owners of the Outstanding Notes, create and issue additional notes of this series of Securities so as to increase the aggregate principal amount of Notes Outstanding in compliance with the procedures set forth in the Indenture, including Sections 2.03 and 2.04 thereof, by issuing additional Securities having the same ranking, interest rate, maturity and other terms (except for the issue date, public offering price and, in some cases, the first Interest Payment Date and the date from which interest shall begin to accrue) as the Notes then Outstanding; provided, further, that any such additional Securities will constitute part of the same series as the Notes issued on the Closing Date; and provided, further, that if the Issuers issue such additional Securities that are not fungible for U.S. federal income tax purposes with the Notes issued on the Closing Date, the additional Securities will have a separate CUSIP number.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) The form and terms of the Notes have been established pursuant to authority duly granted by the Board Resolutions of the Company, adopted on February 15, 2023 (the "<u>Company Board Resolutions</u>"), and the Board Resolutions of AGH, adopted on February 21, 2023 (together, the "<u>Co-Issuer Board Resolutions</u>" and together, the "<u>Board Resolutions</u>"), in accordance with Section 2.03 of the Indenture, and the Corporate Secretary of the Company has certified that the Board Resolutions have been duly adopted by the Board of Directors of the Company and are in full force and effect on the date of such certification and the Corporate Secretary of the Co-Issuer has certified that the Board Resolutions have been duly adopted by the Board of Directors of the Co-Issuer and are in full force and effect on the date of such certification.

SECTION 2.02. <u>Terms of the Notes</u>. The following terms relate to the Notes:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) The Notes hereby established are a series of Securities having the title "5.350% senior notes due 2033 with full and unconditional guarantees as to payment of principal and interest by Aon plc and Aon Global Limited" in and pursuant to authority duly granted by the Board Resolutions the terms and provisions of the Notes as provided for in Section 2.01 of the Indenture with the further terms and provisions as set forth in the form of the Notes attached hereto as <u>Exhibit A</u>.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) The initial aggregate principal amount of the Notes that may be issued, authenticated and delivered under the Indenture (except for Notes authenticated and delivered upon registration of, transfer of, or in exchange for, or in lieu of, other Notes or Notes authenticated and delivered as Additional Securities pursuant to Section 2.01 of the Base Indenture) is $750,000,000.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) The Stated Maturity on which the principal of the Notes shall be due and payable (unless earlier redeemed) shall be February 28, 2033.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) The principal of the Notes shall bear interest at the rate of 5.350% per annum, which interest shall accrue from the most recent Interest Payment Date with respect to the Notes to which interest has been paid or duly provided for, and if no interest has been paid or duly provided for, from and including February 28, 2023, payable semi-annually in arrears on February 28 and August 28 (each, an "<u>Interest Payment Date</u>") in each year, commencing August 28, 2023, to the Persons in whose names the Notes are registered at the close of business on the February 13 or August 13 immediately preceding such Interest Payment Dates (each, a "<u>Regular Record Date</u>") regardless of whether such Regular Record Date is a Business Day.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e) Interest on the Notes shall be calculated on the basis of a 360-day year of twelve 30-day months. Except as described below for the first Interest Payment Date, on each Interest Payment Date, the Issuer will pay interest on the Notes for the period commencing on (and including) the immediately preceding Interest Payment Date and ending on (and including) the day immediately preceding that Interest Payment Date. On the first Interest Payment Date, the Issuer will pay interest for the period beginning on (and including) the Issue Date to (but excluding) the first Interest Payment Date. If any Interest Payment Date falls on a day that is not a Business Day, the related interest payment shall be postponed to the next day that is a Business Day, and no interest on such payment shall accrue for the period from and after such Interest Payment Date. If the Stated Maturity or date of earlier redemption falls on a day that is not a Business Day, payment of principal and interest on such Notes will be made on the next succeeding day that is a Business Day, and no interest will accrue for the period from and after such Stated Maturity or date of earlier redemption. "<u>Business Day</u>" means any day, other than Saturday or Sunday, that is neither a legal holiday nor a day on which banking institutions are authorized or required by law, regulation or executive order to close in the City of New York.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f) Prior to the Par Call Date, the Issuers may redeem the Notes at their option, in whole or in part, at any time and from time to time, at a redemption price (expressed as a percentage of the principal amount and rounded to three decimal places) equal to the greater of:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) (a) the sum of the present values of the remaining scheduled payments of principal and interest on the Notes being redeemed discounted to the redemption date (assuming the Notes matured on the Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate (as defined below), plus 25 basis points (0.250%) less, (b) interest accrued to the date of redemption, and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(ii) 100% of the principal amount of the Notes being redeemed;

plus, in either case, accrued and unpaid interest on the principal amount of the Notes being redeemed to the redemption date.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(g) On or after the Par Call Date, the Issuers may redeem the Notes, in whole or in part, at any time and from time to time, at a redemption price equal to 100% of the principal amount of the Notes being redeemed, plus accrued and unpaid interest thereon to the redemption date.

Notwithstanding the foregoing, installments of interest on Notes being redeemed that are due and payable on interest payment dates falling on or prior to a redemption date will be payable on the interest payment date to the registered holders as of the close of business on the relevant record date according to such Notes and the Indenture.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(h) All payments of interest and principal, including payments made upon any redemption or repurchase of the Notes, will be payable in U.S. Dollars.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) The Notes are designated, pursuant to Section 2.01 of the Indenture, as being entitled to the benefits of the Guarantees of Aon Ireland and Aon UK, and Article Fifteen of the Base Indenture shall apply, and inure to the benefit of, the Notes.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(j) The Notes are subject to redemption at the option of the Issuers as provided in the form of Note attached hereto as <u>Exhibit</u> <u>A</u> and in the Indenture.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(k) The Notes shall have such other terms and provisions as are set forth in the form of Note attached hereto as <u>Exhibit A</u> (all of which are incorporated by reference in and made a part of this Fifth Indenture Supplement as if set forth in full at this place).

SECTION 2.03. <u>Denominations</u>. The Notes shall be issued in registered form without interest coupons and only in minimum denominations of $2,000 and integral multiples of $1,000 in excess thereof.

SECTION 2.04. <u>Form</u>. The Notes will be represented by one or more Global Securities. The Notes shall be in substantially the form set forth in <u>Exhibit</u> <u>A</u> hereto with such changes therein as may be authorized by any officer of the Company and the Co-Issuer executing such Notes by manual, facsimile or electronic signature, such approval to be conclusively evidenced by the execution thereof by such applicable officer.

The terms and provisions contained in the Notes shall constitute, and are hereby expressly made, a part of this Fifth Indenture Supplement, and the Company, the Co-Issuer and the Trustee, by their execution and delivery of this Fifth Indenture Supplement, expressly agree to such terms and provisions and to be bound thereby. However, to the extent any provision of any Note conflicts with the express provisions of this Fifth Indenture Supplement, the provisions of this Fifth Indenture Supplement shall govern and be controlling.

The Notes shall be issued as registered Securities without coupons.

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ARTICLE III

AMENDMENTS TO INDENTURE FOR THE BENEFIT

OF HOLDERS OF THE NOTES

SECTION 3.01. <u>Amendment to Section</u> <u>4.01—Payment of Principal, Premium and Interest</u>. Section 4.01 of the Base Indenture is deleted in its entirety and is hereby replaced and superseded with the following provision:

"**Section 4.01. Payment of Principal, Premium and Interest**. The Issuers will duly and punctually pay or cause to be paid the principal of and premium, if any, and interest, if any, on the Notes, at the place, at the respective times and in the manner provided in the terms of the Notes and in this Indenture. The interest on the Notes shall be payable only to or upon the written order of the Holders thereof and at the option of the Issuers may be paid by wire transfer, other electronic means or mailing checks for such interest payable to or upon the order of such Holders at their last addresses as they appear on the Security Register for such Notes.

SECTION 3.02. <u>Amendment to Section</u> <u>4.02—Offices for Notices and Payments, etc.</u> Section 4.02 of the Base Indenture each reference to "the Company" is deleted and is hereby replaced with "the Issuers".

SECTION 3.03. <u>Amendment to Section</u> <u>4.03—Provisions as to Paying Agent.</u> In Section 4.03 of the Base Indenture each reference to "the Company" is deleted and is hereby replaced with "the Issuers"; *provided that* Section 4.03(b) is deleted in its entirety and is hereby replaced and superseded with the following provision:

"(b) If either the Company or the Co-Issuer shall act as its own paying agent, it will, on or before each due date of the principal of and premium, if any, and interest, if any, on the Securities of any series set aside, segregate and hold in trust for the benefit of the Holders of the Securities of such series entitled thereto a sum sufficient to pay such principal, premium, or interest so becoming due. The applicable Issuer will promptly notify the Trustee of any failure to take such action."

SECTION 3.04. <u>Amendment to Section</u> <u>4.04—Statement by Officers as to Default.</u> Section 4.04 of the Base Indenture shall be deleted in its entirety and is hereby replaced and superseded with the following provision:

**"Section 4.04. Statement by Officers as to Default**.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) Either the Company or the Co-Issuer will deliver to the Trustee, on or before a date not more than four months after the end of each fiscal year of the Company or the Co-Issuer, as applicable, ending after the date hereof, an Officers' Certificate of the Company or the Co-Issuer, as applicable, which shall include the statements provided for in Section 16.04 and stating whether or not to the best knowledge of the signers thereof either the Company or the Co-Issuer is in default in the performance or observance of any of the terms, provisions and conditions of this Indenture to be performed or observed by it and specifying all such defaults and the nature thereof of which it may have knowledge.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) The Company and the Co-Issuer, as applicable, will deliver to the Trustee, as soon as practicable upon becoming aware of any default (which word has the meaning of the word "default" as used in Section 6.07) or Event of Default with respect to a particular series of Securities that has occurred and is continuing, a written notice setting forth the details of such default or Event of Default."

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SECTION 3.05. <u>Amendment to Section</u> <u>4.05—Payment of Additional Amounts</u>. Section 4.05 of the Base Indenture is deleted in its entirety and is hereby replaced and superseded with the following provision:

**"Section 4.05. Payment of Additional Amounts**.<u> </u>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) All payments made by any Guarantor (including any successor in interest to any of the foregoing) in respect of its Guarantee shall be made free and clear of and without withholding or deduction for or on account of any present or future income, stamp or other tax, duty, levy, impost, assessment or other governmental charge of any nature whatsoever imposed or levied by or on behalf of the government of the United Kingdom or Ireland, as applicable, or, in each case, by any authority or agency therein or thereof having the power to tax (collectively, "<u>Taxes</u>"), unless such Guarantor is required to withhold or deduct Taxes by law.

If a Guarantor is required to withhold or deduct any amount for or on account of Taxes from any payment made with respect to its Guarantee, such Guarantor shall pay such additional amounts (the "<u>Additional Amounts</u>") as may be necessary in order that the net amounts received in respect of such payments by the beneficial owner, the Trustee or any Agent, as the case may be, after such withholding or deduction (including any such deduction or withholding from such Additional Amounts), shall not be less than the amounts that would have been received in respect of such payments on the Guarantees in the absence of such withholding or deduction; provided however that no such Additional Amounts will be payable with respect to Taxes:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(1) that would not have been so imposed or levied but for the existence of any present or former connection between the relevant Holder or beneficial owner of the Notes (or between a fiduciary, settlor, beneficiary, member or shareholder of, or possessor of a power over, such Holder or beneficial owner, if such Holder or beneficial owner is an estate, trust, partnership or corporation), and the United Kingdom or Ireland, as applicable, or, in each case, any political subdivision or territory or possession thereof or therein or area subject to its jurisdiction, including, without limitation, such Holder or beneficial owner (or such fiduciary, settlor, beneficiary, member, shareholder or possessor) being or having been a citizen or resident thereof or treated as a resident thereof or domiciled thereof or a national thereof or being or having been present or engaged in trade or business therein or having or having had a permanent establishment therein;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(2) that are estate, inheritance, gift, sales, transfer, personal property, wealth or similar taxes, duties, assessments or other governmental charges;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(3) payable other than by withholding from payments in respect of a Guarantee;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(4) that would not have been so imposed but for the failure of the applicable recipient of such payment to comply with any certification, identification, information, documentation or other reporting requirement to the extent:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) such compliance is required by applicable law or administrative practice or an applicable treaty as a precondition to exemption from, or reduction in, the rate of deduction or withholding of such Taxes; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(ii) at least thirty (30) days before the first payment date with respect to which such Additional Amounts shall be payable, such Guarantor has notified such recipient in writing that such recipient is required to comply with such requirement;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(5) that would not have been imposed but for the presentation of a Note (where presentation is required) for payment on a date more than thirty (30) days after the date on which such payment became due and payable or the date on which payment thereof was duly provided for, whichever occurred later;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(6) that are imposed or withheld pursuant to Sections 1471 through 1474 of the U.S. Internal Revenue Code of 1986, as amended (the "<u>Code</u>"), as of the issue date of the Notes (or any amended or successor version of such sections), any regulations promulgated thereunder, any official interpretations thereof, and any similar law or regulation adopted pursuant to an intergovernmental agreement between a non-U.S. jurisdiction and the United States with respect to the foregoing or any agreements entered into pursuant to Section 1471(b)(1) of the Code;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(7) that would not have been imposed if presentation for payment of the relevant Notes or a Guarantee (where presentation is required), had been made to a paying agent other than the paying agent to which the presentation was made; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(8) any combination of the foregoing clauses (1) through (8);

nor shall Additional Amounts be paid with respect to any payment in respect of a Guarantee, to any such Holder or beneficial owner who is a fiduciary or a partnership or a beneficial owner who is other than the sole beneficial owner of such payment to the extent a beneficiary or settlor with respect to such fiduciary or a member of such partnership or a beneficial owner would not have been entitled to such Additional Amounts had it been the Holder of the Note.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) For avoidance of doubt, no Additional Amounts shall be paid with respect to or on account of any present or future income, stamp or other tax, duty, levy, impost, assessment or other governmental charge of any nature whatsoever imposed or levied by or on behalf of the government of the United States or the United Kingdom relating to payments by the Issuers under the Notes.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) All references in this Indenture, other than in Articles Twelve or Thirteen of the Base Indenture, to the payment of the principal of or premium, if any, or interest, if any, on or the net proceeds received on the sale or exchange of, any Notes or any payment made under a Guarantee shall be deemed to include Additional Amounts to the extent that, in that context, Additional Amounts are, were or would be payable in respect thereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) The obligations of each Guarantor to pay Additional Amounts if and when due will survive the termination of this Indenture and the payment of all other amounts in respect of the Notes."

SECTION 3.06. <u>Amendment to Section</u> <u>11.01—Company and Guarantors May Consolidate, etc., on Certain Terms</u>. Section 11.01 of the Base Indenture is deleted in its entirety and is hereby replaced and superseded with the following provision:

"**Section 11.01. Company, the Co-Issuer and Guarantors May Consolidate, etc., Only on Certain Terms**. So long as any Securities shall be Outstanding, none of the Company, the Co-Issuer or, with respect to any series of Securities to which the provisions of Article Fifteen shall apply, any Guarantor shall consolidate with or merge or convert into any other Person or convey, transfer or lease its properties and assets substantially as an entirety to any Person unless:

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) (1) The Company, the Co-Issuer or such Guarantor, as the case may be, is the surviving entity, or (2) the Person formed by such consolidation or conversion or into which the Company, the Co-Issuer or such Guarantor, as applicable, is merged or converted or the Person which acquires by conveyance or transfer, or which leases, the properties and assets of the Company, the Co-Issuer or such Guarantor, as the case may be, substantially as an entirety:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) expressly assumes, by an indenture supplemental hereto, executed and delivered to the Trustee, in form satisfactory to the Trustee, in the case of the Company and/or the Co-Issuer, the due and punctual payment of the principal of and premium, if any, and interest, if any, on all the Securities and the performance of every covenant of this Indenture on the part of the Company and/or the Co-Issuer, as applicable, to be performed or observed or, in the case of such Guarantor, with respect to any series of Securities to which the provisions of Article Fifteen shall apply, the due and punctual payment of all payment obligations under the Guarantee and the performance of every other covenant of this Indenture on the part of such Guarantor to be performed or observed and which supplemental indenture shall provide for conversion or exchange rights in accordance with the provisions of the Securities of any series that are convertible or exchangeable into Shares or other securities, if any such Securities are then outstanding; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(ii) in the case of the Company, is a corporation or other entity organized and existing under the laws of the United States, any State thereof or the District of Columbia.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) immediately after giving effect to such transaction and treating any indebtedness which becomes an obligation of the Company, the Co-Issuer or such Guarantor, as applicable, as a result of such transaction as having been incurred by the Company, the Co-Issuer or such Guarantor, as applicable, at the time of such transaction, no Event of Default, and no event which, after notice or lapse of time or both, would become an Event of Default, shall have happened and be continuing; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) the Company and/or the Co-Issuer, as applicable, has delivered to the Trustee an Officers' Certificate of the Company, the Co-Issuer or such Guarantor has delivered to the Trustee an Officers' Certificate of such Guarantor, as the case may be, and, in either case, an Opinion of Counsel, each stating that such consolidation, merger, conversion, conveyance, transfer or lease and, if a supplemental indenture is required in connection with such transaction, such supplemental indenture comply with this Article and that all conditions precedent herein provided for relating to such transaction have been complied with."

SECTION 3.07. <u>Amendment to Section</u> <u>11.02—Successor Person Substituted</u>. Section 11.02 of the Base Indenture is deleted in its entirety and is hereby replaced and superseded with the following provision:

"**Section 11.02. Successor Person Substituted**. So long as any Notes shall be outstanding, upon any consolidation, merger or conversion, or any conveyance, transfer or lease of the properties and assets of the Company, the Co-Issuer or any Guarantor substantially as an entirety, in accordance with Section 11.01, the successor Person formed by such consolidation or into which the Company, the Co-Issuer or such Guarantor, as applicable, is merged or converted or to which such conveyance, transfer or lease is made shall succeed to, and be substituted for, and may exercise every right and power of, the Company, the Co-Issuer or such Guarantor, as the

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case may be, under this Indenture with the same effect as if such successor Person had been named as the Company, the Co-Issuer or a Guarantor, as the case may be, herein, and thereafter, except in the case of a lease, the predecessor Person shall be relieved of all obligations and covenants under this Indenture and the Notes."

ARTICLE IV

MISCELLANEOUS

SECTION 4.01. <u>Ratification</u>. This Fifth Indenture Supplement shall be deemed part of the Base Indenture in the manner and to the extent herein provided. Except as expressly amended hereby, the Base Indenture is in all respects ratified and confirmed and all the terms, conditions and provisions thereof shall remain in full force and effect.

SECTION 4.02. <u>Provisions Binding on Successors</u>. All the covenants, stipulations, promises and agreements in this Fifth Indenture Supplement contained by or on behalf of the Company, the Co-Issuer or the Guarantors shall bind their respective successors and assigns, whether so expressed or not.

SECTION 4.03. <u>Counterparts</u>. This Fifth Indenture Supplement and the Global Securities may be executed in any number of counterparts, each of which so executed shall be deemed an original, but all of such counterparts shall together constitute but one and the same instrument. The use of electronic signatures and electronic records (including, without limitation, any contract or other record created, generated, sent, communicated, received, or stored by electronic means) shall be of the same legal effect, validity and enforceability as a manually executed signature or use of a paper- based record-keeping system to the fullest extent permitted by applicable law, including the Federal Electronic Signatures in Global and National Commerce Act, the New York State Electronic Signatures and Records Act, and any other applicable law, including, without limitation, any state law based on the Uniform Electronic Transactions Act or the Uniform Commercial Code.

SECTION 4.04. <u>Governing Law</u>. This Fifth Indenture Supplement shall be governed by and construed in accordance with the laws of the State of New York, without regard to the principles of conflicts of laws.

SECTION 4.05. <u>Separability</u>. In case any one or more of the provisions contained in this Fifth Indenture Supplement or in the Notes shall for any reason be held to be invalid, illegal or unenforceable in any respect, such invalidity, illegality or unenforceability shall not affect any other provisions of this Fifth Indenture Supplement or of such Notes, but this Fifth Indenture Supplement and such Notes shall be construed as if such invalid or illegal or unenforceable provision had never been contained herein or therein.

SECTION 4.06. <u>Governing Law.</u> This Fifth Indenture Supplement shall be governed by and construed in accordance with the laws of the State of New York, without regard to the principles of conflicts of laws.

SECTION 4.07. <u>Trustee.</u> The Trustee makes no representation as to the validity or sufficiency of this Fifth Indenture Supplement. The recitals contained herein shall be taken as the statements of the Company, the Co-Issuer and the Trustee assumes no responsibility for their correctness. The Trustee shall have the right to accept and act upon instructions, including funds transfer instructions ("<u>Instructions</u>") given pursuant to this Indenture and delivered using Electronic Means; provided, however, that the Company and the Co-Issuer shall provide to the Trustee an incumbency certificate

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listing officers with the authority to provide such Instructions ("<u>Authorized Officers</u>") and containing specimen signatures of such Authorized Officers, which incumbency certificate shall be amended by the Company and the Co-Issuer whenever a person is to be added or deleted from the listing. If the Company or the Co-Issuer elects to give the Trustee Instructions using Electronic Means and the Trustee in its discretion elects to act upon such Instructions, the Trustee's understanding of such Instructions shall be deemed controlling. Each of the Company and the Co-Issuer understands and agrees that the Trustee cannot determine the identity of the actual sender of such Instructions and that the Trustee shall conclusively presume that directions that purport to have been sent by an Authorized Officer listed on the incumbency certificate provided to the Trustee have been sent by such Authorized Officer. The Company and the Co-Issuer shall be responsible for ensuring that only Authorized Officers transmit such Instructions to the Trustee and that the Company and the Co-Issuer and all Authorized Officers are solely responsible to safeguard the use and confidentiality of applicable user and authorization codes, passwords and/or authentication keys upon receipt by the Company and the Co-Issuer. The Trustee shall not be liable for any losses, costs or expenses arising directly or indirectly from the Trustee's reliance upon and compliance with such Instructions notwithstanding such directions conflict or are inconsistent with a subsequent written instruction. Each of the Company and the Co-Issuer agrees: (i) to assume all risks arising out of the use of Electronic Means to submit Instructions to the Trustee, including without limitation the risk of the Trustee acting on unauthorized Instructions, and the risk of interception and misuse by third parties; (ii) that it is fully informed of the protections and risks associated with the various methods of transmitting Instructions to the Trustee and that there may be more secure methods of transmitting Instructions than the method(s) selected by the Company or the Co-Issuer, as the case may be; (iii) that the security procedures (if any) to be followed in connection with its transmission of Instructions provide to it a commercially reasonable degree of protection in light of its particular needs and circumstances; and (iv) to notify the Trustee immediately upon learning of any compromise or unauthorized use of the security procedures. The Trustee may execute this Fifth Indenture Supplement and any other documents delivered pursuant hereto (including authentication of the Notes) via Electronic Means.

"<u>Electronic Means</u>" shall mean the following communications methods: S.W.1.F.T., e-mail, facsimile transmission, secure electronic transmission containing applicable authorization codes, passwords and/or authentication keys issued by the Trustee, or another method or system specified by the Trustee as available for use in connection with its services hereunder.

[*Signature Pages Follow*]

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IN WITNESS WHEREOF, each of the parties hereto has caused this Fifth Indenture Supplement to be duly signed, all as of the day and year first above written.

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| | |
|:---|:---|
| **AON CORPORATION**, A CORPORATION DULY ORGANIZED AND EXISTING UNDER THE LAWS OF THE STATE OF DELAWARE | **AON CORPORATION**, A CORPORATION DULY ORGANIZED AND EXISTING UNDER THE LAWS OF THE STATE OF DELAWARE |
| BY: | /s/ Julie Cho |
|  | NAME: JULIE CHO |
|  | TITLE: VICE PRESIDENT AND SECRETARY |
| **AON GLOBAL HOLDINGS PLC**, A PUBLIC LIMITED COMPANY DULY ORGANIZED AND EXISTING UNDER THE LAWS OF ENGLAND AND WALES | **AON GLOBAL HOLDINGS PLC**, A PUBLIC LIMITED COMPANY DULY ORGANIZED AND EXISTING UNDER THE LAWS OF ENGLAND AND WALES |
| BY: | /s/ Gardner Mugashu |
|  | NAME: GARDNER MUGASHU |
|  | TITLE: DIRECTOR |
| **AON PLC**, A PUBLIC LIMITED COMPANY DULY ORGANIZED AND EXISTING UNDER THE LAWS OF IRELAND | **AON PLC**, A PUBLIC LIMITED COMPANY DULY ORGANIZED AND EXISTING UNDER THE LAWS OF IRELAND |
| BY: | /s/ Paul Hagy |
|  | NAME: PAUL HAGY |
|  | TITLE: TREASURER |
| **AON GLOBAL LIMITED**, A PRIVATE LIMITED COMPANY DULY ORGANIZED AND EXISTING UNDER THE LAWS OF ENGLAND AND WALES | **AON GLOBAL LIMITED**, A PRIVATE LIMITED COMPANY DULY ORGANIZED AND EXISTING UNDER THE LAWS OF ENGLAND AND WALES |
| BY: | /s/ Alistair Boyd |
|  | NAME: ALISTAIR BOYD |
|  | TITLE: DIRECTOR |

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[*Company Signature Page to the Indenture Supplement*]

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| | |
|:---|:---|
| **THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A.** | **THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A.** |
| BY: | /s/ Michele R. Shrum |
|  | NAME: Michele R. Shrum |
|  | TITLE: VICE PRESIDENT |

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[*Trustee Signature Page to the Indenture Supplement*]

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<u>EXHIBIT A</u> 

FORM OF NOTE

Unless this Security is presented by an authorized representative of The Depository Trust Company (55 Water Street, New York, New York) to the issuer or its agent for registration of transfer, exchange or payment, and any Security issued upon registration of transfer of, or in exchange for, or in lieu of, this Security is registered in the name of Cede & Co. or such other name as requested by an authorized representative of The Depository Trust Company and any payment hereon is made to Cede & Co., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL since the registered owner hereof, Cede & Co., has an interest herein.

**AON CORPORATION** 

**AON GLOBAL HOLDINGS PLC** 

**$750,000,000 5.350% Senior Notes Due 2033** 

**with full and unconditional guarantees** 

**as to payment of principal and interest by** 

**Aon plc and Aon Global Limited** 

**No. [ ]** 

**$[ ]** 

**CUSIP No. 03740L AG7** 

**AON CORPORATION** 

**AON GLOBAL HOLDINGS PLC** 

Aon Corporation, a Delaware corporation (herein called the "**Company**," which term includes any successor Person under the Indenture hereinafter referred to) and Aon Global Holdings plc, a public limited company formed under the laws of England and Wales (hereinafter called the "**Co-Issuer**," which term includes any successor Person under the Indenture hereinafter referred to, and, together with the Company, the "**Issuers**"), for value received, hereby, jointly and severally, promise to pay to Cede & Co., as nominee for The Depository Trust Company, or registered assigns, the principal sum of **[[ ]** ($)**]** on February 28, 2033 and, subject to Section 16.05 of said Indenture, to pay interest thereon from February 28, 2023 or from the most recent Interest Payment Date to which interest has been paid or duly provided for, semi-annually in arrears on each February 28 and August 28, commencing August 28, 2023 (each, an "**Interest Payment Date**"), at the rate of 5.350% per annum, until the principal hereof is paid or made available for payment. The interest so payable, and punctually paid or duly provided for, on any Interest Payment Date will, as provided in such Indenture, be paid to the Person in whose name this Security (or one or more predecessor Securities) is registered at the close of business on the Regular Record Date for such interest, which shall be February 13 or August 13 (whether or not a Business Day), as the case may be, immediately preceding such Interest Payment Date. Any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose name this Security (or one or more predecessor Securities) is registered at the close of business on a subsequent record date for the payment of such defaulted interest established by the Company and the Co-Issuer, notice whereof shall be given to Holders of Securities of this series not less than 15 days prior to such subsequent record date, such record date to be not less than 5 days preceding the date of payment of such defaulted interest, or be paid at any time in any other lawful manner not inconsistent with the requirements of any securities exchange on which the Securities of this series may be listed, and upon such notice as may be required by such exchange, all as more fully provided in said Indenture.

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Payment of the principal of (and premium, if any) and any such interest on this Security will be made at the office or agency of the Company maintained for that purpose in the City of Chicago or the Borough of Manhattan, The City of New York, in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts; <u>provided</u>, <u>however</u>, that at the option of the Company or the Co-Issuer payment of interest may be made by wire transfer, other electronic means or mailing checks to the address of the Holder entitled thereto as such address shall appear in the Security Register.

The Securities of this series are subject to redemption and repurchase at the option of the Issuers prior to the stated maturity as described in the Indenture and on the reverse hereof.

Reference is hereby made to the further provisions of this Security set forth on the reverse hereof, which further provisions shall for all purposes have the same effect as if set forth at this place.

Unless the certificate of authentication hereon has been executed by the Trustee referred to herein by manual, facsimile or electronic signature, this Security shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose.

NOTICE TO HOLDER

THE HOLDER OF THIS SECURITY IS HEREBY NOTIFIED, AND BY ITS ACCEPTANCE HEREOF ACKNOWLEDGES, THAT (1) THE COMPANY, THE CO-ISSUER AND A GUARANTOR, IN RESPECT OF ITS GUARANTEE, SHALL WITHHOLD OR DEDUCT FOR OR ON ACCOUNT OF ANY PRESENT OR FUTURE INCOME, STAMP OR OTHER TAX, DUTY, LEVY, IMPOST, ASSESSMENT OR OTHER GOVERNMENTAL CHARGE OF ANY NATURE WHATSOEVER IMPOSED OR LEVIED BY OR ON BEHALF OF THE GOVERNMENT OF THE UNITED STATES OR BY ANY AUTHORITY OR AGENCY THEREIN OR THEREOF HAVING THE POWER TO TAX (COLLECTIVELY, "UNITED STATES TAXES") AS REQUIRED BY LAW OF THE UNITED STATES AND (2) IF THE COMPANY, THE CO-ISSUER OR A GUARANTOR (OR WITHHOLDING AGENT FOR THE COMPANY, THE CO-ISSUER OR GUARANTOR) IS SO REQUIRED TO WITHHOLD OR DEDUCT ANY AMOUNT FOR OR ON ACCOUNT OF UNITED STATES TAXES FROM ANY PAYMENT, NO ADDITIONAL AMOUNTS SHALL BE PAID TO A HOLDER OR BENEFICIAL OWNER FOR OR WITH RESPECT TO THE AMOUNT SO WITHHELD OR DEDUCTED.

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IN WITNESS WHEREOF, the Company and the Co-Issuer have caused this instrument to be duly executed.

Dated: February 28, 2023

---

| | |
|:---|:---|
| **AON CORPORATION,** A CORPORATION DULY ORGANIZED AND EXISTING UNDER THE LAWS OF THE STATE OF DELAWARE | **AON CORPORATION,** A CORPORATION DULY ORGANIZED AND EXISTING UNDER THE LAWS OF THE STATE OF DELAWARE |
| By: |  |
|  | Name: Paul Hagy |
|  | Title: Senior Vice President and Treasurer |
| **AON GLOBAL HOLDINGS PLC,** A PUBLIC LIMITED COMPANY DULY ORGANIZED AND EXISTING UNDER THE LAWS OF ENGLAND AND WALES | **AON GLOBAL HOLDINGS PLC,** A PUBLIC LIMITED COMPANY DULY ORGANIZED AND EXISTING UNDER THE LAWS OF ENGLAND AND WALES |
| By: |  |
|  | Name: Gardner Mugashu |
|  | Title: Director |

---

---

| |
|:---|
| Attest: |
| Name: Julie Cho |
| Title: Vice President and Secretary |

---

*[Company Signature Page to the Note]*

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This is one of the Securities of the series designated therein referred to in the within-mentioned Indenture.

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| | | |
|:---|:---|:---|
|  | **THE BANK OF NEW YORK MELLON TRUSTCOMPANY, N.A.,**<br>as Trustee | **THE BANK OF NEW YORK MELLON TRUSTCOMPANY, N.A.,**<br>as Trustee |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Dated: February 28, 2023 | By: |  |
|  |  | Authorized Officer |

---

*[Trustee Signature Page to the Note]* 

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This Security is one of a duly authorized series of securities of the Company and the Co-Issuer entitled "5.350% Senior Notes Due 2033" (herein called the "**Securities**") issued and to be issued in one or more series under the Amended and Restated Indenture, dated April 1, 2020, as supplemented by the Fifth Indenture Supplement, dated February 28, 2023, among the Company, the Co-Issuer, the Guarantors and The Bank of New York Mellon Trust Company, N.A., as Trustee (herein called the "**Trustee**," which term includes any successor trustee under the Indenture, as defined below) (together, the "**Indenture**"), to which Indenture and all indentures supplemental thereto reference is hereby made for a statement of the respective rights, limitations of rights, duties and immunities thereunder of the Company, the Co-Issuer, the Trustee and the Holders of the Securities and of the terms upon which the Securities are, and are to be, authenticated and delivered. The Securities of this series will initially be issued in the aggregate principal amount of $750,000,000. The Issuers may, from time to time, without the written consent of or notice to Holders of the Securities of this series, create and issue under the Indenture additional securities having the same terms and conditions as the Securities of this series (other than the issue date, the issue price and, to the extent applicable, the first date from which interest on such additional securities shall accrue and the first interest payment date for such additional securities) and such additional securities shall be consolidated with and form a single series with the Securities of this series.

Prior to November 28, 2032 (three months prior to the Securities' Stated Maturity) (the "**Par Call Date**"), the Issuers may redeem the Securities at their option, in whole or in part, at any time and from time to time, at a redemption price (expressed as a percentage of the principal amount and rounded to three decimal places) equal to the greater of (i) (a) the sum of the present values of the remaining scheduled payments of principal and interest on the Securities being redeemed discounted to the redemption date (assuming the Securities being redeemed matured on the applicable Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate, plus 25 basis points (0.250%) less, (b) interest accrued to the date of redemption, and (ii) 100% of the principal amount of the Securities being redeemed; and plus, in either case, accrued and unpaid interest on the principal amount of the Securities being redeemed to the redemption date.

On or after the Par Call Date, the Issuers may redeem the Securities, in whole or in part, at any time and from time to time, at a redemption price equal to 100% of the principal amount of the Securities being redeemed plus accrued and unpaid interest thereon to the redemption date.

"**Treasury Rate**" means, with respect to any redemption date, the yield determined by the Issuers in accordance with the following two paragraphs:

The Treasury Rate shall be determined by the Issuers after 4:15 p.m., New York City time (or after such time as yields on U.S. government securities are posted daily by the Board of Governors of the Federal Reserve System), on the third business day preceding the redemption date based upon the yield or yields for the most recent day that appear after such time on such day in the most recent statistical release published by the Board of Governors of the Federal Reserve System designated as "Selected Interest Rates (Daily)—H.15" (or any successor designation or publication) ("**H.15**") under the caption "U.S. government securities–Treasury constant maturities–Nominal" (or any successor caption or heading). In determining the Treasury Rate, the Issuers shall select, as applicable: (1) the yield for the Treasury constant maturity on H.15 exactly equal to the period from the redemption date to the Par Call Date (the "**Remaining Life**"); or (2) if there is no such Treasury constant maturity on H.15 exactly equal to the Remaining Life, the two yields – one yield corresponding to the Treasury constant maturity on H.15 immediately shorter than and one yield corresponding to the Treasury constant maturity on H.15 immediately longer than the Remaining Life – and shall interpolate to the Par Call Date on a straight-line basis (using the actual number of days) using such yields and rounding the result to three decimal places; or (3) if there is no such Treasury constant maturity on H.15 shorter than or longer than the Remaining Life, the yield for the single Treasury constant maturity on H.15 closest to the Remaining Life. For purposes of this paragraph, the applicable Treasury constant maturity or maturities on H.15 shall be deemed to have a maturity date equal to the relevant number of months or years, as applicable, of such Treasury constant maturity from the redemption date.

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If on the third business day preceding the redemption date H.15 is no longer published, the Issuers shall calculate the Treasury Rate based on the rate per annum equal to the semi-annual equivalent yield to maturity at 11:00 a.m., New York City time, on the second business day preceding such redemption date of the United States Treasury security maturing on, or with a maturity that is closest to, the Par Call Date, as applicable. If there is no United States Treasury security maturing on the Par Call Date but there are two or more United States Treasury securities with a maturity date equally distant from the Par Call Date, one with a maturity date preceding the Par Call Date and one with a maturity date following the Par Call Date, the Issuers shall select the United States Treasury security with a maturity date preceding the Par Call Date. If there are two or more United States Treasury securities maturing on the Par Call Date or two or more United States Treasury securities meeting the criteria of the preceding sentence, the Issuers shall select from among these two or more United States Treasury securities the United States Treasury security that is trading closest to par based upon the average of the bid and asked prices for such United States Treasury securities at 11:00 a.m., New York City time. In determining the Treasury Rate in accordance with the terms of this paragraph, the semi-annual yield to maturity of the applicable United States Treasury security shall be based upon the average of the bid and asked prices (expressed as a percentage of principal amount) at 11:00 a.m., New York City time, of such United States Treasury security, and rounded to three decimal places.

Notice of any redemption will be mailed or electronically delivered (or otherwise transmitted in accordance with the depositary's procedures) at least 10 days but not more than 60 days before the redemption date to each Holder of Securities to be redeemed. In the case of a partial redemption, selection of Securities in certificated form for redemption will be made by lot. Unless the Issuers and the Guarantors default in payment of the redemption price, on and after the redemption date, interest will cease to accrue on the Securities or portions thereof called for redemption. In the case of a partial redemption, selection of the Securities for redemption will be made pro rata, by lot or by such other method as the Trustee in its sole discretion deems appropriate and fair. For so long as the Securities are held by The Depository Trust Company (or another depositary), the redemption of the Notes shall be done in accordance with the policies and procedures of the depositary.

The Issuers' actions and determinations in determining the redemption price shall be conclusive and binding for all purposes, absent manifest error.

Notwithstanding the foregoing, installments of interest on Securities being redeemed that are due and payable on Interest Payment Dates falling on or prior to a redemption date will be payable on the Interest Payment Date to the registered Holders as of the close of business on the Regular Record Date according to the Securities and the Indenture.

All payments made by a Guarantor with respect to its Guarantee shall be made free and clear of and without withholding or deduction for or on account of any present or future income, stamp or other tax, duty, levy, impost, assessment or other governmental charge of any nature whatsoever imposed or levied by or on behalf of the government of the United Kingdom or Ireland, as applicable, or, in each case, by any authority or agency therein or thereof having the power to tax (collectively, "**Taxes**"), unless such Guarantor is required to withhold or deduct Taxes by law.

If an Event of Default with respect to the Securities of this series shall occur and be continuing, the principal amount of and accrued and unpaid interest, if any, on the Securities of this series may be declared due and payable in the manner and with the effect provided in the Indenture.

The Indenture contains provisions for defeasance at any time of the entire indebtedness of this Security or certain restrictive covenants and Events of Default with respect to this Security, in each case upon compliance with certain conditions set forth therein.

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The Indenture permits, with certain exceptions as therein provided, the amendment thereof and the modification of the rights and obligations of the Company and the Co-Issuer and the rights of the Holders of the Securities of each series to be affected under the Indenture at any time by the Company, the Co-Issuer and the Trustee with the consent of the Holders of a majority in principal amount of the Securities at the time Outstanding of each series to be affected. The Indenture also contains provisions permitting the Holders of specified percentages in principal amount of the Securities of each series at the time Outstanding, on behalf of the Holders of all Securities of such series, to waive compliance by the Company and the Co-Issuer with certain provisions of the Indenture and certain past defaults under the Indenture and their consequences. Any such consent or waiver by the Holder of this Security shall be conclusive and binding upon such Holder and upon all future Holders of this Security and of any Security issued upon the registration of transfer hereof or in exchange herefor or in lieu hereof, whether or not notation of such consent or waiver is made upon this Security.

No reference herein to the Indenture and no provision of this Security or of the Indenture shall alter or impair the obligation of the Company and the Co-Issuer, which is joint and several, absolute and unconditional, to pay the principal of and any premium and interest on this Security at the times, place and rate, and in the coin or currency, herein prescribed.

As provided in the Indenture and subject to certain limitations therein set forth, the transfer of this Security is registerable in the Security Register, upon surrender of this Security for registration of transfer at the office or agency of the Company or the Co-Issuer in any place where the principal of and any premium and interest on this Security are payable, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Company, the Co-Issuer and the Security Registrar duly executed by, the Holder hereof or his attorney duly authorized in writing, and thereupon one or more new Securities of this series and of like tenor, of authorized denominations and for the same aggregate principal amount, will be issued to the designated transferee or transferees.

The Securities of this series are issuable only in registered form without coupons in denominations of $2,000 and integral multiples of $1,000. As provided in the Indenture and subject to certain limitations therein set forth, Securities of this series are exchangeable for a like aggregate principal amount of Securities of this series and of like tenor of a different authorized denomination, as requested by the Holder surrendering the same.

No service charge shall be made for any such registration of transfer or exchange, but the Issuers may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith.

Prior to due presentment of this Security for registration of transfer, the Company, the Co-Issuer, the Trustee and any agent of the Company, the Co-Issuer or the Trustee may treat the Person in whose name this Security is registered as the owner hereof for all purposes, whether or not this Security be overdue, and none of the Company, the Co-Issuer, the Trustee or any such agent shall be affected by notice to the contrary.

Interest on this Security shall be computed on the basis of a 360-day year consisting of twelve 30-day months. Except as described below for the first Interest Payment Date, on each Interest Payment Date, the Issuer will pay interest on the Notes for the period commencing on (and including) the immediately preceding Interest Payment Date and ending on (and including) the day immediately preceding that Interest Payment Date. On the first Interest Payment Date, the Issuer will pay interest for the period beginning on (and including) the Issue Date to (but excluding) the first Interest Payment Date. If any Interest Payment Date falls on a day that is not a Business Day, the related interest payment shall be postponed to the next day that is a Business Day, and no interest on such payment shall accrue for the period from and after such Interest Payment Date. If the Stated Maturity or date of earlier redemption falls on a day that is not a Business Day, payment of principal and interest on such Notes will be made on the next succeeding day that is a Business Day, and no interest will accrue for the period from and after such Stated Maturity or date of earlier redemption. "**Business Day**" means any day, other than Saturday or Sunday, that is neither a legal holiday nor a day on which banking institutions are authorized or required by law, regulation or executive order to close in the City of New York.

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All terms used but not defined in this Security which are defined in the Indenture shall have the meanings assigned to them in the Indenture.

This Security shall be governed by and construed in accordance with the laws of the State of New York without giving effect to the conflict of laws provisions thereof.

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**ASSIGNMENT** 

I or we assign and transfer this Security to:

_________________________________________

(Insert assignee's social security or tax I.D. number)

_________________________________________

(Print or type name, address and zip code of assignee)

and irrevocably appoint:

as agent to transfer this Security on the books of the Company and the Co-Issuer. The agent may substitute another to act for him.

Date: _______________________ Your Signature:     <br> (Sign exactly as your name appears on the face of<br>this Security)

Signature Guarantee: _________________________________________

Signatures must be guaranteed by an "eligible guarantor institution" meeting the requirements of the Security Registrar, which requirements include membership or participation in the Security Transfer Agent Medallion Program ("**STAMP**") or such other "signature guarantee program" as may be determined by the Security Registrar in addition to, or in substitution for, STAMP, all in accordance with the Securities Exchange Act of 1934, as amended.

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**NOTATION OF GUARANTEE** 

For value received, the undersigned Guarantor (which term includes any successor Person under the Indenture), subject to the provisions in the Indenture and the terms of the Securities of this series, has fully, unconditionally and irrevocably guaranteed to and for the benefit of each Holder and the Trustee the due and prompt payment in full of all amounts which may at any time be or become from time to time due and payable by the Company and the Co-Issuer under the Indenture or otherwise with respect to the Securities of this series registered in such Holder's name, at their stated due dates or when otherwise due in accordance with the terms thereof. The obligations of the Guarantor to the Holders of Securities and to the Trustee pursuant to the Guarantee under the Indenture are expressly set forth in Article Fifteen of the Indenture and reference is hereby made to the Indenture for the precise terms of the Guarantee. Each Holder of a Security, by accepting the same, (a) agrees to and shall be bound by such provisions and (b) appoints the Trustee attorney-in-fact of such Holder for the purpose of such provisions.

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| | |
|:---|:---|
| **Aon plc,** a public limited company duly organized and existing under the laws of Ireland | **Aon plc,** a public limited company duly organized and existing under the laws of Ireland |
| By: |  |
|  | Name: Paul Hagy |
|  | Title: Senior Vice President and Treasurer |

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[*Signature Page to the Notation of Guarantee*]

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**NOTATION OF GUARANTEE** 

For value received, the undersigned Guarantor (which term includes any successor Person under the Indenture), subject to the provisions in the Indenture and the terms of the Securities of this series, has fully, unconditionally and irrevocably guaranteed to and for the benefit of each Holder and the Trustee the due and prompt payment in full of all amounts which may at any time be or become from time to time due and payable by the Company and the Co-Issuer under the Indenture or otherwise with respect to the Securities of this series registered in such Holder's name, at their stated due dates or when otherwise due in accordance with the terms thereof. The obligations of the Guarantor to the Holders of Securities and to the Trustee pursuant to the Guarantee under the Indenture are expressly set forth in Article Fifteen of the Indenture and reference is hereby made to the Indenture for the precise terms of the Guarantee. Each Holder of a Security, by accepting the same, (a) agrees to and shall be bound by such provisions and (b) appoints the Trustee attorney-in-fact of such Holder for the purpose of such provisions.

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| | |
|:---|:---|
| **Aon Global Limited,** a private limited company duly organized and existing under the laws of England and Wales | **Aon Global Limited,** a private limited company duly organized and existing under the laws of England and Wales |
| By: |  |
|  | Name: Alistair Patrick Boyd |
|  | Title: Director |

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[*Signature Page to the Notation of Guarantee*]

## Exhibit 5.1

**Exhibit 5.1** 

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| | |
|:---|:---|
| ![LOGO](g474704g0228054206755.jpg)  | SIDLEY AUSTIN LLP<br> 787 SEVENTH AVENUE<br> NEW YORK, NY 10019<br> +1 212 839 5300<br> +1 212 839 5599 FAX<br>AMERICA • ASIA PACIFIC • EUROPE |

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February 28, 2023

Aon Corporation

200 East Randolph Street

Chicago, IL 60601

Aon Global Holdings plc

The Aon Centre

The Leadenhall Building

122 Leadenhall Street

London, UK EC3V 4AN

Aon plc

James Joyce Street

Dublin 1

D01 K0Y8

Ireland

Aon Global Limited

8 Devonshire Square

London, UK X0 EC2M 4PL

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| | |
|:---|:---|
| Re: | U.S. $750,000,000 5.350% Senior Notes due 2033 issued by Aon Corporation and Aon Global Holdings plc under the Registration Statement on Form S-3 (Registration Nos. 333-238189, 333-238189-01, 333-238189-02 and 333-238189-03) with full and unconditional guarantees as to payment of principal and interest by, among others, Aon plc and Aon Global Limited (each, a "<u>Guarantor</u>" and, together, the "<u>Guarantors</u>")  |

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Ladies and Gentlemen:

We refer to the Registration Statement on Form S-3ASR, File Nos. 333-238189, 333-238189-01, 333-238189-02 and 333-238189-03 (the "<u>Registration Statement</u>"), filed by) for the registration of debt securities of Aon Corporation, a Delaware corporation (the "<u>Company")</u>, Aon Global Holdings plc, a public limited company organized under the laws of England and Wales (the "<u>Co-Issuer</u>" and, together with the Company, the "<u>Issuers</u>") and Aon plc, a public limited company organized under the laws of Ireland ("<u>Aon plc</u>"), guarantees of the

Sidley Austin (NY) LLP is a Delaware limited liability partnership doing business as Sidley Austin LLP and practicing in affiliation with other Sidley Austin partnerships.

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![LOGO](g474704g0228054206755.jpg)

Aon Corporation, Aon Global Holdings plc, Aon plc and Aon Global Limited

February 28, 2023

Issuers and the Guarantors and certain other securities of Aon plc under the Securities Act of 1933, as amended (the "<u>1933 Act</u>"), which Registration Statement became effective upon filing pursuant to Rule 462(e) under the Securities Act. Pursuant to the Registration Statement, the Issuers are issuing $750,000,000 aggregate principal amount of 5.350% Senior Notes due 2033 (the "<u>Notes</u>"). The Guarantors are providing a guarantee of the Notes (the "<u>Guarantee</u>" and, together with the Notes, the "<u>Securities</u>") pursuant to a guarantee endorsed (the "<u>Guarantee Endorsement</u>") on the certificates evidencing the Notes and the Indenture (as defined below). The Securities are being issued under an Amended and Restated Indenture dated as of April 1, 2020 (the "<u>Original Indenture</u>") among the Company, as issuer, the Co-Issuer and the Guarantors, as guarantors, and The Bank of New York Mellon Trust Company, N.A., as trustee (the "<u>Trustee</u>") (amending and restating an Indenture dated as of December 3, 2018, among the Company, as issuer, AGL, as guarantor, and the Trustee) as amended and supplemented by a Supplemental Indenture thereto dated as of February 28, 2023 (the "<u>Supplemental Indenture</u>") among the Issuers, the Guarantors and the Trustee (the Original Indenture, as amended and supplemented by the Supplemental Indenture, the "<u>Indenture</u>"). The Securities are to be sold by the Company pursuant to an underwriting agreement dated February 23, 2023 (the "<u>Underwriting Agreement</u>") among the Issuers, the Guarantors and the underwriters named in Exhibit A thereto.

This opinion letter is being delivered in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act.

In rendering the opinions expressed below, we have examined the Registration Statement, the Indenture, the Underwriting Agreement, the Notes in global form and the resolutions adopted by the board of directors of the Guarantors relating to the offering, the Indenture, the Underwriting Agreement and the issuance of the Guarantee by the Guarantors. We have also examined originals, or copies of originals certified to our satisfaction, of such agreements, documents, certificates and statements of each of the Issuers and the Guarantors and other corporate documents and instruments, and have examined such questions of law, as we have considered relevant and necessary as a basis for this opinion letter. We have assumed the authenticity of all documents submitted to us as originals, the genuineness of all signatures, the legal capacity of all persons and the conformity with the original documents of any copies thereof submitted to us for examination. As to facts relevant to the opinions expressed herein, we have relied without independent investigation or verification upon, and assumed the accuracy and completeness of, certificates, letters and oral and written statements and representations of public officials and officers and other representatives of each of the Issuers and the Guarantors.

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![LOGO](g474704g0228054206755.jpg)

Aon Corporation, Aon Global Holdings plc, Aon plc and Aon Global Limited

February 28, 2023

Based on and subject to the foregoing and the other limitations, qualifications and assumptions set forth herein, we are of the opinion that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. The Notes will constitute valid and binding obligations of the Issuers when the Notes have been duly executed by duly authorized officers of the Issuers and duly authenticated by the Trustee, all in accordance with the provisions of the Indenture, and delivered to the purchasers thereof against payment of the agreed consideration therefor in accordance with the Underwriting Agreement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. The Guarantee has been duly authorized by the Guarantors. The Guarantee will constitute a valid and binding obligation of the Guarantors when the Notes have been duly executed by duly authorized officers of the Company and duly authenticated by the Trustee, all in accordance with the provisions of the Indenture, and delivered to the purchasers thereof against payment of the agreed consideration therefor in accordance with the Underwriting Agreement, and the Guarantee Endorsement has been duly executed by an authorized officer of the Guarantors.

The foregoing opinions are subject to bankruptcy, insolvency, reorganization, moratorium, fraudulent conveyance, fraudulent transfer and other similar laws relating to or affecting creditors' rights generally and to general equitable principles (regardless of whether considered in a proceeding in equity or at law), including concepts of commercial reasonableness, good faith and fair dealing and the possible unavailability of specific performance or injunctive relief. The foregoing opinions are also subject to (i) provisions of law which may require that a judgment for money damages rendered by a court in the United States of America be expressed only in United States dollars, (ii) requirements that a claim with respect to any debt securities or other obligations that are denominated or payable other than in United States dollars (or a judgment denominated or payable other than in United States dollars in respect of such claim) be converted into United States dollars at a rate of exchange prevailing on a date determined pursuant to applicable law and (iii) governmental authority to limit, delay or prohibit the making of payments outside of the United States of America or in a foreign currency.

With respect to each instrument or agreement referred to in or otherwise relevant to the opinions set forth herein (each, an "<u>Instrument</u>"), we have assumed, to the extent relevant to the opinions set forth herein, that (i) each party to such Instrument (if not a natural person) was duly organized or formed, as the case may be, and was at all relevant times and is validly existing and in good standing under the laws of its jurisdiction of organization or formation, as the case may be, and had at all relevant times and has full right, power and authority to execute, deliver and perform its obligations under such Instrument and (ii) such Instrument has been duly authorized, executed and delivered by, and was at all relevant times and is a valid, binding and enforceable agreement or obligation, as the case may be, of, each party thereto; <u>provided</u> that we make no such assumption insofar as any of the foregoing matters relates to (a) the Issuers and is expressly covered by our opinions set forth in paragraph 1. above or (b) the Guarantors.

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![LOGO](g474704g0228054206755.jpg)

Aon Corporation, Aon Global Holdings plc, Aon plc and Aon Global Limited

February 28, 2023

This opinion letter is limited to the General Corporation Law of the State of Delaware and the laws of the State of New York (excluding the securities laws of the State of New York). We express no opinion as to the laws, rules or regulations of any other jurisdiction, including, without limitation, the federal laws of the United States of America or any state securities or blue sky laws or the laws of England and Wales.

We hereby consent to the filing of this opinion letter as an exhibit to the Company's Current Report on Form 8-K dated February 28, 2023 and the incorporation by reference of this opinion letter as an exhibit to the above-referenced Registration Statement and to the use of our name wherever it appears in the Registration Statement. In giving such consent, we do not thereby admit that we are within the category of persons whose consent is required by Section 7 of the Securities Act.

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| |
|:---|
| Very truly yours, |
| /s/ Sidley Austin LLP |

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## Exhibit 5.2

![LOGO](g474704g77y43.jpg)

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| | |
|:---|:---|
|  | **London** |
|  | Freshfields Bruckhaus Deringer LLP |
|  | 100 Bishopsgate |
|  | London EC2P 2SR |
|  | +44 20 7936 4000 (Switchboard) |
|  | +44 20 7832 7022 (Direct) |
| F | +44 20 7108 7022 |
|  **Aon Global Holdings plc** | LDE No 23 |
|  The Aon Centre | peter.allen@freshfields.com |
|  The Leadenhall Building | www.freshfields.com |
|  122 Leadenhall Street |  |
|  London, EC3V 4AN |  |

---

28 February 2023

**Aon Global Holdings plc and Aon Corporation** 

**Prospectus Supplement to Registration Statement on Form S-3ASR** 

**Introduction** 

1. In connection with the automatic shelf registration statement on Form S-3ASR (the ***Registration Statement***) filed with the U.S. Securities and Exchange Commission (***SEC***) on 12 May 2020, as supplemented by a prospectus supplement dated 23 February 2023 and filed with the SEC on 24 February 2023 (the ***Prospectus Supplement***) of Aon Global Holdings plc, a public limited company incorporated under the laws of England and Wales (***AGH***), and Aon Corporation, a Delaware corporation (and together with AGH, the ***Co-Issuers***), under the United States Securities Act of 1933, as amended (the ***Securities Act***), we have been requested to render our opinion on certain matters in connection with the Prospectus Supplement. The Registration Statement and Prospectus Supplement relate to the registration under the Securities Act of the issuance and sale of US$750,000,000 aggregate principal amount of 5.350% senior notes due 2033, issued by the Co-Issuers (the ***Debt Securities***). The Debt Securities will be fully and unconditionally guaranteed, jointly and severally, by Aon plc, an Irish public limited company and Aon Global Limited, a private limited company incorporated under the laws of England and Wales (formerly known as Aon plc) (***AGL*** and, together with Aon plc, the ***Guarantors***).

2. We are acting as English legal advisers to AGH and AGL, for the purposes of giving this opinion. In so acting, we have examined the following documents:

(a) the Prospectus Supplement;

Freshfields Bruckhaus Deringer LLP is a limited liability partnership registered in England and Wales with registered number OC334789. It is authorised and regulated by the Solicitors Regulation Authority (SRA no. 484861). For further regulatory information please refer to www.freshfields.com/support/legal-notice.

A list of the members (and of the non-members who are designated as 'partners') of Freshfields Bruckhaus Deringer LLP is available for inspection at its registered office, 100 Bishopsgate, London EC2P 2SR. Any reference to a 'partner' means a member, or a consultant or employee with equivalent standing and qualifications, of Freshfields Bruckhaus Deringer LLP or any associated firms or entities.

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(b) a copy of the underwriting agreement of the Co-Issuers, the Guarantors,
Morgan Stanley & Co. LLC, BofA Securities, Inc. and HSBC Securities (USA) Inc. dated 23 February 2023 (the  ***Underwriting Agreement***);

(c) a copy of the current Articles of Association of AGH as at 28 February 2023;

(d) a copy of AGH's Certificate of Incorporation dated 16 September 2014, issued by the Registrar of
Companies of England and Wales, together with a copy of AGH's Certificate of Incorporation on re-registration of a private limited company as a public limited company dated 29 April 2020 ((c) and
(d) together the  ***AGH Constitutional Documents***);

(e) a copy of the current Articles of Association of AGL as at 28 February 2023;

(f) a copy of AGL's Certificate of Incorporation dated 8 December 2011, issued by the Registrar of
Companies of England and Wales, together with copies of AGL's Certificate of Incorporation on change of name dated 23 December 2011, Certificate of Incorporation on change of name and registration of a private company as a public company
dated 30 March 2012 and Certificate of Incorporation on change of name and registration of a public company as a private company dated 15 July 2020 ((e) and (f) together the  ***AGL Constitutional Documents*** and, together
with the AGH Constitutional Documents, the  ***Constitutional Documents***);

(g) a copy of the indenture dated 3 December 2018 entered into between the Co-Issuers, the Guarantors and the Bank of New York Mellon, as trustee, as supplemented by the amended and restated indenture dated 1 April 2020, as further supplemented by the second indenture supplement
dated 2 December 2021, the third indenture supplement dated 28 February 2022, the fourth indenture supplement dated 12 September 2022 and the fifth indenture supplement dated 28 February 2023 under which the Debt Securities are
to be issued (the  ***Indenture***) containing the guarantee of the Debt Securities by the Guarantors (the  ***Guarantee***) (the Indenture and the Underwriting Agreement together, the  ***Documents***);

(h) searches carried out on 28 February 2023 with respect to each of AGH and AGL (carried out by us or by
LegalinX Limited trading as GlobalX on our behalf) of the public documents of AGH and AGL kept at Companies House in Cardiff (the  ***Company Searches***);

(i) a winding up enquiry of the Central Registry of Winding up Petitions (carried out by us or by GlobalX on our
behalf) on 28 February 2023 with respect to each of AGH and AGL (the  ***Winding-up Enquiry***);

(j) a certificate issued to us by the Company Secretary of AGH dated 28 February 2023 (the  ***AGH Secretary's Certificate***);

(k) a certificate issued to us by the Company Secretary of AGL dated 28 February 2023 (the  ***AGL Secretary's Certificate*** and together with the AGH Secretary's Certificate, the  ***Secretaries' Certificates***);

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(l) written resolutions of the board of directors of AGH approved on 21 February 2023 authorising the
execution and delivery of and performance of obligations under the Indenture, the issue of term debt by AGH as a Co-Issuer and the execution and delivery of and performance of obligations under the Debt
Securities; and

(m) written resolutions of the board of directors of AGL approved on 21 February 2023 authorising the
execution and delivery of and performance of obligations under the Indenture and the execution and delivery of and performance of obligations under, when issued, the Debt Securities and the Guarantee,

and relied upon the statements as to factual matters contained in or made pursuant to each of the above mentioned documents.

3. This opinion is confined to matters of English law (including case law) as at the date of this opinion and is governed by and should be construed in accordance with English law. By giving this opinion, we do not assume any obligation to notify you of future changes in law which may affect the opinions expressed in this opinion or otherwise to update this opinion in any respect. Accordingly, we express no opinion herein with regard to any system of law other than the laws of England as currently applied by the English courts. We express no opinion as to whether or not a foreign court (applying its own conflict rules) will act in accordance with the parties' agreement as to jurisdiction and/or choice of law or uphold the terms of the Documents or the Debt Securities. A reference in this opinion to a statutory provision (including for the avoidance of doubt any onshored EU legislation) is to it as amended.

4. We express no opinion herein in respect of the tax treatment of the above documents or the transactions contemplated by such documents, and you have not relied on any advice from us herein in relation to the tax implications of such matters, for you or any other person, whether in the United Kingdom or in any other jurisdiction, or the suitability of any tax provisions in the above documents.

5. To the extent that the laws of the United States, the laws of the State of New York or the Delaware Limited Liability Company Act may be relevant, our opinion is subject to the effect of such laws including the matters contained in the opinion of Sidley Austin LLP and to the extent that the laws of the Ireland may be relevant, our opinion is subject to the effect of such laws including the matters contained in the opinion of Matheson. We express no views on the validity of the matters set out in such opinions.

**Assumptions** 

6. In considering the above documents and in rendering this opinion we have with your consent and without any further enquiry assumed:

(a)  ***Authenticity*** : (A) the genuineness of all signatures, (B) that a signatory has
personally signed each Document either (i) by hand (a  ***wet ink signatory***); or (ii) by adding an image or their signature to an electronic version of the Document; or (iii) by adding their signature to an electronic
version of the Document on an approved web-based electronic signing platform ( ***e-platform***) contemplated by the parties; or (iv) by using a mouse,
finger, stylus or similar to sign their name in an electronic version of the Document on a touchscreen device such as an iPad (each signature referred to in (ii) to (iv) an  ***e-signature*** , and
each signatory referred to in (ii) to (iv) an  ***e-signatory***), and (C) the genuineness of all stamps and seals on, and the authenticity, accuracy and completeness of, all documents submitted to
us (whether as originals or copies);

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(b)  ***Copies*** : the conformity to originals of all documents supplied to us as photocopies, portable
document format (PDF) copies, facsimile copies or e-mail conformed copies;

(c)  ***Witnessing*** : that where a document has been witnessed, each witness has personally witnessed the
signature of that document by the person whose signature they are witnessing and has applied its own witness signature or authorised its witness signature to be appended to the final text or any electronic version of the final text of the document
only after doing so;

(d)  ***Virtual Signings*** : that the parties have complied with the procedures for counterpart signature
and delivery of the Documents contemplated by the parties and their legal advisers and that the parties have validly authorised the attachment of their respective signature pages to the final texts of the Documents;

(e)  ***Confirmation by Counsel*** : in any case where a party's counsel has attached and released the
signature pages of that party's counterparts of the Documents, that such counsel had all necessary authority from that party to do so;

(f)  ***Drafts*** : that, where a document has been examined by us in draft or specimen form, it will be or
has been executed in the form of that draft or specimen;

(g)  ***Secretaries' Certificates:*** that each of the statements contained in the Secretaries'
Certificates is true and correct as at the date hereof;

(h)  ***Written Resolutions:*** that the written resolutions approved by AGL on 21 February 2023, as
evidenced by the written resolutions included in the AGL Secretary's Certificate, were properly passed, that all provisions contained in the Companies Act 2006 and the Articles of Association of AGL relating to the disclosure of directors'
interests and the power of interested directors to vote were duly observed, and that such resolutions have not been amended, modified or revoked and are in full force and effect; the directors of AGL having any interest in any of the matters duly
disclosed their interest therein and were entitled to approve the written resolutions; and such resolutions remain in full force and effect without modification;

(i)  ***Written Resolutions:*** that the written resolutions approved by AGH on 21 February 2023, as
evidenced by the written resolutions included in the AGH Secretary's Certificate, were properly passed, that all provisions contained in the Companies Act 2006 and the Articles of Association of AGH relating to the disclosure of directors'
interests and the power of interested directors to vote were duly observed, and that such resolutions have not been amended, modified or revoked and are in full force and effect; the directors of AGH having any interest in any of the matters duly
disclosed their interest therein and were entitled to approve the written resolutions; and such resolutions remain in full force and effect without modification;

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(j)  ***Corporate Power:*** that each of the parties to the Documents (other than AGH and AGL) has the
necessary capacity and corporate power to execute, deliver and perform its obligations under the Documents, and that the Documents have been duly authorised and executed and delivered by each of the parties thereto in accordance with all applicable
laws (other than in the case of AGH and AGL, the laws of England) in the form filed as an exhibit to the Registration Statement;

(k)  ***Validity under all laws*** : that the Documents and, when issued, the Debt Securities constitute
legal, valid and binding obligations of each of the parties thereto enforceable under all applicable laws including the laws of the United States and the laws of the State of New York by which they are expressed to be governed (other than in the
case of AGH and AGL, the laws of England); that satisfactory evidence of the laws of the United States and the State of New York, which is required to be pleaded and proved as a fact in any proceedings before the English Courts, could be so pleaded
and proved; and that insofar as the laws and regulations of any other jurisdiction may be relevant to (i) the obligations or rights of any of the parties under the Documents, or (ii) any of the transactions contemplated by the Documents,
such laws and regulations do not prohibit, and are not inconsistent with, the entering into and performance of any such obligations, rights or transactions;

(l)  ***Filings under all laws*** : that all consents, licences, approvals, notices, filings, recordations,
publications and registrations which are necessary under any applicable laws (other than, in the case of AGH and AGL, the laws of England) in order to permit the execution, delivery or performance of the Documents or to perfect, protect or preserve

(m)  ***No Amendments*** : that the Documents have not been amended, terminated, rescinded or varied, that
there has been no breach of any of its provisions by any of the parties thereto which would affect the opinions expressed in this opinion, and that the Documents are not affected in any way by any relevant provisions of any other document or
agreement or any course of dealings between the parties thereto;

(n)  ***Unknown Facts*** : that there are no facts or circumstances (and no documents, agreements,
instruments or correspondence) which are not apparent from the face of the documents we have reviewed or which have not been disclosed to us that may affect the validity or enforceability of the Documents or any obligation therein or otherwise
affect the opinions expressed in this opinion;

(o)  ***Arm's Length Terms*** : that the Documents have been entered into for bona fide commercial
reasons and on arm's length terms by each of the parties thereto;

(p)  ***Directors' Duties:*** that the directors of AGL and AGL in authorising the execution and
delivery of and performance of obligations under the Documents and, when issued, the Debt Securities have exercised their powers in accordance with their duties under all applicable laws and the Constitutional Documents, as applicable, in force at
the applicable time;

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(q)  ***FSMA:*** that the sale of the Debt Securities or the consummation by AGH and AGL of the transactions
contemplated by the Documents (as relevant) will not constitute an "offer to the public" within the meaning of Part VI of the Financial Services and Markets Act 2000 (the  ***FSMA***) and does not require the publication by the Co-Issuers of a prospectus pursuant to Onshored Regulation (EU) 2017/1129, as it forms part of the laws of the United Kingdom by virtue of the European Union (Withdrawal) Act 2018;

(r)  ***Authorisation under FSMA*** : that each person dealing with AGH and/or AGL in connection with the
Debt Securities which is carrying on, or purporting to carry on, a regulated activity (within the meaning of section 19 of the Financial Services and Markets Act 2000) is an authorised person or an exempt person for the purposes of the FSMA;

(s)  ***FSMA (Financial promotion):*** that the Registration Statement and the Prospectus Supplement
(including any such document in draft and preliminary form) and any other invitation or inducement to engage in investment activity (within the meaning of section 21 of the FSMA) in connection with the issue or sale of the Debt Securities has only
been and will only be communicated or caused to be communicated in circumstances in which section 21(1) of the FSMA does not apply to AGH and/or AGL;

(t)  ***Company Searches:*** that the information revealed by the Company Searches: (i) was accurate in
all respects and has not since the time of such search been altered; and (ii) was complete, and included all relevant information which had been properly submitted to the Registrar of Companies;

(u)  ***Winding up Enquiry*** : that the information revealed by our Winding-up Enquiry was accurate in all respects and has not since the time of such enquiry been altered;

(v)  ***Representations*** : that the terms of the Documents and Underwriting Agreement, other than, in the
case of the Underwriting Agreement, as to matters of law on which we opine in this opinion, have been and will be observed and performed by the parties thereto;

(w)  ***Financial crime, national security and investment, antitrust and criminal cartel, sanctions, pensions and human rights etc*** : that the parties to the Documents and all persons representing them have complied (and will continue to comply) with all applicable anti-terrorism, national security and investment laws, anti-corruption, anti- money
laundering, anti-tax evasion, other financial crime, civil or criminal antitrust, cartel, competition, public procurement, state aid, anti-subsidy, sanctions, pensions and human rights laws and regulations
which may affect them, the transactions contemplated by the Documents or the Documents, and that performance and enforcement of them, the transactions contemplated by the Documents or the Documents is, and will continue to be, consistent with all
such laws and regulations; and

(x)  ***Bad Faith, Fraud, Duress*** : the absence of bad faith, breach of duty, breach of trust, fraud,
coercion, duress or undue influence on the part of any of the parties to the Documents and their respective directors, employees, agents and advisers (excepting ourselves).

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**Opinion** 

7. On the basis of and subject to the foregoing and the matters set out in paragraphs 8 and 9 below and any matters not disclosed to us, and having regard to such considerations of English law in force, as at the date of this letter as we consider relevant, we are of the opinion that:

(a)  ***Corporate Existence:*** AGH has been duly incorporated in the United Kingdom and registered in
England and Wales as a public limited company and AGL has been duly incorporated in the United Kingdom and registered in England and Wales as private limited company;

(b)  ***Corporate Power:*** (i) AGH has the requisite corporate power and capacity to issue, deliver
and perform its obligations under, when issued, the Debt Securities in accordance with the terms of the Indenture and (ii) AGL has the requisite corporate power and capacity to issue, deliver and perform its obligations under, when issued, the
Guarantee, in accordance with the terms of the Guarantee and the Indenture;

(c)  ***Corporate Authority:*** (i) AGH has taken steps required under English law and the AGH
Constitutional Documents to authorise AGH to enter into and perform its obligations under, when issued, the Debt Securities in accordance with the terms of the Indenture and (ii) AGL has taken steps required under English law and the AGL
Constitutional Documents to authorise AGL to enter into and perform its obligations under, when issued, the Guarantee in accordance with the terms of the Indenture; and

(d)  ***No Violation*** : the execution and delivery of the Debt Securities and the Documents and the
performance of AGH's and AGL's obligations thereunder (in accordance with the terms of the relevant Document) have been respectively duly authorised by all necessary corporate action on the part of AGH and AGL and do not and will not of
themselves result in any violation by AGH or AGL of any term of their respective Constitutional Documents or of any law or regulation having the force of law in England and applicable to AGH or AGL as to performance.

**Qualifications** 

8. Our opinion is subject to the following qualifications:

(a)  ***Company Searches:*** the Company Searches are not capable of revealing conclusively whether or not:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) a winding-up order has been made or a resolution passed for the
winding- up of a company; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(ii) an administration order has been made; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(iii) a receiver, administrative receiver, administrator or liquidator has been appointed; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(iv) a court order has been made under the Cross-Border Insolvency Regulations 2006,

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since notice of these matters may not be filed with the Registrar of Companies immediately and, when filed, may not be entered on the public records of the relevant company immediately.

In addition, the Company Searches are not capable of revealing, prior to the making of the relevant order or the appointment of an administrator otherwise taking effect, whether or not a winding-up petition or an application for an administration order has been presented or notice of intention to appoint an administrator under paragraphs 14 or 22 of Schedule B1 to the Insolvency Act 1986 has been filed with the court;

(b)  ***Winding up Enquiry*** : the Winding-up Enquiry relates only
to the presentation of: (i) a petition for the making of a winding-up order or the making of a winding-up order by the court, (ii) an application to the High
Court of Justice in London for the making of an administration order and the making by such court of an administration order, (iii) a notice of intention to appoint an administrator or a notice of appointment of an administrator filed at the
High Court of Justice in London, and (iv) a notice of a moratorium under Part A1 of the Insolvency Act 1986. It is not capable of revealing conclusively whether or not such a winding-up petition,
application for an administration order, notice of intention, notice of appointment or notice of a moratorium has been presented or winding-up or administration order granted, because:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) details of a winding-up petition or application for an administration
order may not have been entered on the records of the Central Registry of Winding-up Petitions immediately;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(ii) in the case of (A) an application for the making of an administration order; (B) the filing of a
notice of intention to appoint an administrator; (C) the filing of a notice of appointment of an administrator; or (D) the filing of a notice of a moratorium, if such application is made to, order made by or notice filed with, a court
other than the High Court of Justice in London, no record of such application, order or notice will be kept by the Central Registry of Winding-up Petitions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(iii) a winding-up order or administration order may be made before the
relevant petition or application has been entered on the records of the Central Registry, and the making of such order may not have been entered on the records immediately;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(iv) details of a notice of intention to appoint an administrator or a notice of appointment of an administrator
under paragraphs 14 and 22 of Schedule B1 of the Insolvency Act 1986 may not be entered on the records immediately (or, in the case of a notice of intention to appoint, at all); and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(v) with regard to winding-up petitions, the Central Registry of Winding-up Petitions may not have records of winding-up petitions issued prior to 1994;

(c)  ***Foreign Courts:*** no opinion is given as to whether or not the chosen court will take jurisdiction
(applying its own conflict rules), or act in accordance with the parties' agreement as to choice of law or whether the English courts would grant a stay of any proceedings commenced in England, or whether the English courts would grant any
ancillary relief in relation to proceedings commenced in a foreign court;

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(d)  ***Financial Limitations*** : no opinion is given as to the compliance or otherwise with: (i) the
financial limitations on borrowings or covenants by each of AGH and AGL contained in the relevant Constitutional Documents; or (ii) the limitations on the maximum aggregate principal amount of the Debt Securities which may be issued by the Co-Issuers and irrevocably guaranteed by the Guarantors as contemplated by the Registration Statement; and

(e)  ***Insolvency*** : this opinion is subject to all applicable laws relating to insolvency, bankruptcy,
administration, moratorium, reorganisation, liquidation or analogous circumstances and other similar laws of general application relating to or affecting generally the enforcement of creditor's rights and remedies from time to time.

**Observations** 

9. ***Factual Statements****:* It should be understood that we have not been responsible for investigating or verifying the accuracy of the facts, including the statements of foreign law, or the reasonableness of any statement or opinion or intention contained in or relevant to any document referred to herein, or that no material facts have been omitted therefrom. This opinion is also given on the basis that we undertake no responsibility to notify you of any change in English law after the date of this opinion.

10. ***Pensions***: In giving this opinion, we have not considered whether the transactions contemplated by the Documents including the issuance of the Debt Securities might constitute a criminal offence or otherwise attract criminal liability under the amendments made by the UK Pension Schemes Act 2021 to the UK Pensions Act 2004.

11. ***National Security & Investment Act 2021***: We have not considered whether the transactions contemplated by the Documents including the issuance of the Debt Securities comply with the National Security & Investment Act 2021, nor whether any filings, clearances, notifications or disclosures are required or advisable under such law.

**Benefit of Opinion** 

12. This opinion is addressed to you solely for your own benefit for the purposes of the Registration Statement and the Prospectus Supplement to be filed under the Securities Act and, except with our prior written consent, is not to be transmitted or disclosed to or used or relied upon by any other person or used or relied upon by you for any other purpose. Your reliance on the matters addressed in this opinion letter is on the basis that any associated recourse is against the firm's assets only and not against the personal assets of any individual partner. The firm's assets for this purpose consist of all assets of the firm's business, including any right of indemnity of the firm or its partners under the firm's professional indemnity insurance policies, but excluding any right to seek contribution or indemnity from or against any partner of the firm or person working for the firm or similar right. The restrictions in the previous sentences apply to any claim, whether in contract, tort (including negligence) for breach of statutory duty, or otherwise, but they do not apply in the case of our wilful misconduct or fraud or where and to the extent prohibited by applicable law and regulation (including without limitation, the rules of professional responsibility governing the practice of law).

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Having requested production of this opinion and in order to rely on its contents, you agree to be bound by its terms.

We consent to the filing of this opinion as an Exhibit to the report on Form 8-K to be filed by AGH and Aon Corporation on the date hereof and to the reference to our firm under the heading "Legal Matters" in the Prospectus Supplement. In giving such consent, we do not thereby admit that we are within the category of persons whose consent is required by the Securities Act or by the rules and regulations promulgated thereunder.

Yours faithfully

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Freshfields Bruckhaus Deringer LLP

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## Exhibit 5.3

**Exhibit 5.3**![LOGO](g474704g0228054153708.jpg)

Aon plc Metropolitan Building James Joyce Street Dublin 1 Ireland

Our ref 28 February 2023 <br> FBO/SCC 659500-37

Dear Sirs

**Registration, offer and sale of $750,000,000, 5.350% Senior Notes due 2033 by Aon Corporation and Aon Global Holdings plc, as guaranteed by Aon plc and Aon Global Limited** 

We have acted as Irish counsel to Aon plc, a public limited company incorporated under the laws of Ireland (company number 604607) (the "**Company**"), in connection with the registration, offer and sale of $750,000,000, 5.350% Senior Notes due 2033 by Aon Corporation, a Delaware corporation, and Aon Global Holdings plc, a public limited company incorporated under the laws of England and Wales, as guaranteed by the Company and Aon Global Limited, a private limited company incorporated under the laws of England and Wales, (the "**Notes**") pursuant to the registration statement on Form S-3ASR (the "**Registration Statement**") filed by the Company on 12 May 2020 under the U.S. Securities Act of 1933, as amended (the "**Securities Act**") with the U.S. Securities Exchange Commission (the "**Commission**"), the prospectus included therein and a prospectus supplement dated 23 February 2023 (the "**Prospectus Supplement**").

The Notes will be issued under an amended and restated indenture, dated 1 April 2020, among Aon Corporation, as an issuer, the Company, Aon Global Holdings plc and Aon Global Limited, as guarantors, and the Bank of New York Mellon Trust Company N.A., as trustee, as amended and supplemented by a fifth supplemental indenture, dated 28 February 2023, among Aon Corporation and Aon Global Holdings plc, as co-issuers, the Company and Aon Global Limited, as guarantors, and the Bank of New York Mellon Trust Company N.A., as trustee, (the "**Indenture**").

![LOGO](g474704g0228054154079.jpg)

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![LOGO](g474704g0228054154529.jpg)

The Notes are to be sold pursuant to an underwriting agreement dated 23 February 2023 among Aon Corporation, Aon Global Holdings plc, the Company, Aon Global Limited and the underwriters named therein (the "**Underwriting Agreement**").

In connection with this Opinion, we have reviewed the corporate resolutions, records and other documents and searches listed in Schedule 1 to this Opinion (the "**Documents**").

Based on the foregoing, and subject to the assumptions, qualification and limitations set out in Schedule 2, Schedule 3 and elsewhere in this Opinion, we are of the opinion that:

1. the Company is a public limited company, duly incorporated and validly existing under the laws of Ireland; and

2. the Company has the requisite power and authority under its constitution to enter into the Indenture, to
perform its obligations thereunder and to guarantee the Notes, and the entry into the Indenture and the guarantee of the Notes has been duly authorised by the Company.

This Opinion is based upon, and limited to, the laws of Ireland and is in effect on the date hereof and is based on legislation published and cases fully reported before that date and our knowledge of the facts relevant to the opinions contained herein. We have assumed without enquiry that there is nothing in the laws of any jurisdiction other than Ireland which would, or might, affect our opinion as stated herein. We have made no investigations of, and we express no opinion on, the laws of any jurisdiction other than Ireland or the effect thereof. This Opinion is expressed as of the date hereof and we assume no obligation to update this Opinion.

This Opinion is furnished to you and the persons entitled to rely upon it pursuant to the applicable provisions of the Securities Act strictly for use in connection with the Registration Statement and may not be relied upon by any other person without our prior written consent. This Opinion is confined strictly to the matters expressly stated herein and is not to be read as extending by implication or otherwise to any other matter.

We hereby consent to the filing of this Opinion as Exhibit 5.1 to the Current Report on Form 8-K dated the date hereof filed by the Company and incorporated by reference into the Registration Statement and to the reference to Matheson under the caption "Legal Matters" in the Prospectus Supplement constituting a part of the Registration Statement. In giving such consent, we do not admit that we are included in the category of persons whose consent is required under section 7 of the Securities Act, or the rules and regulations of the Commission promulgated thereunder.

This Opinion and the opinions given in it are governed by, and construed in accordance with, the laws of Ireland.

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| |
|:---|
| Yours faithfully |
| */s/ Matheson LLP* |
| MATHESON LLP |

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![LOGO](g474704g0228054154529.jpg)

**Schedule 1** 

**The Documents** 

1. A certificate issued by the secretary of the Company dated 28 February 2023 (the "**Corporate Certificate** "), attaching a copy of each of the following certified as being true, complete and correct by such director:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) the constitution and certificate of incorporation (and any certificate of incorporation on change of name and
the certificate of incorporation on re-registration) of the Company; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) an extract of the resolutions of the board of directors of the Company passed at a meeting of the board of
directors of the Company held on 18 November 2022.

and certifying certain other matters, as set therein, on which we have relied for the purpose of this Opinion.

2. The Registration Statement, including the prospectus included therein.

3. The Prospectus Supplement.

4. A copy of the Indenture.

5. A copy of the Underwriting Agreement.

6. Searches carried out by independent law researchers on our behalf against the Company on 28 February 2023
in (a) the Index of Petitions and Winding-up Notices maintained at the Central Office of the High Court of Ireland, (b) the Judgments' Office of the Central Office of the High Court of Ireland
and (c) the Companies Registration Office (the "**Searches** ").

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**Schedule 2** 

**Assumptions** 

For the purposes of this Opinion, we have assumed:

1. The truth and accuracy of the contents of the Documents as to factual matters, but have made no independent
investigation regarding such factual matters.

2. All signatures (including, for the avoidance of doubt, electronic signatures), initials, seals and stamps
contained in, or on, the Documents submitted to us are genuine.

3. Any electronic signature inserted on a Document was inserted by the signatory in question and not by another
person and, where attested by a witness, was inserted in the physical presence of the witness, and each other party to any Document which has been executed using electronic signatures has consented to the execution by the Company of that Document by
way of electronic signature.

4. All Documents submitted to us as originals are authentic and complete and all Documents submitted to us as
copies (including without limitation any document submitted to us as a .pdf, or any other format, attachment to an email) are complete and conform to the originals of such Documents, and the originals of such Documents are authentic and complete.

5. The Corporate Certificate is accurate in all respects (other than in relation to any matter of Irish law on
which we expressly opine).

6. Each party to the Documents (other than the Company) had (when it entered into), and continues to have, the due
and requisite capacity, power and authority to enter into, execute and perform its obligations under the Documents, and the Documents are not subject to avoidance by any person under all applicable laws in all applicable jurisdictions (other than in
the case of the Company, the laws of Ireland and the jurisdiction of Ireland).

7. All Documents dated on or prior to the date hereof and on which we have expressed reliance have not been
revoked or amended and remain accurate.

8. The resolutions of the board of directors of the Company on which we have expressed reliance were duly passed
at a properly constituted, convened and quorate meeting of the directors of the Company and such resolutions have not been amended or rescinded and are in full force and effect.

9. The Company has, or will, derive a commercial benefit from entering into the Indenture and any other document
referred to in, or contemplated by, the Registration Statement (including the prospectus contained therein and the Prospectus Supplement) and guaranteeing the Notes in accordance with the provisions of the Indenture commensurate with the obligations
undertaken by it thereunder.

10. In approving the entry into the Indenture and any other document referred to in, or contemplated by, the
Registration Statement (including the prospectus contained therein) and the Prospectus Supplement and guaranteeing the Notes in accordance with the provisions of the Indenture, the directors of the Company have acted in a manner they consider, in
good faith, to be in the interests of the Company for its legitimate business purposes and which would be likely to promote the success of the Company for its members as a whole.

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11. The Company has not, and shall not, by virtue of or in connection with its guarantee of the Notes, give any
financial assistance, as contemplated by sections 82 and 1043 of the Companies Act 2014 of Ireland (the "**Companies Act**") for the purpose of any acquisition of shares in the capital of the Company, save as permitted by, or pursuant
to an exemption to, the said sections 82 and 1043.

12. The Company together with any other entity whose obligations are guaranteed by it under the Indenture together
comprise a "group" for the purposes of section 243 of the Companies Act and any person that subsequently becomes an issuer or a guarantor under the Indenture will also be a member of such group.

13. In entering into the Documents and approving the guarantee of the Notes under the Indenture, there was no
intent by the directors and/or duly authorised officer acting under delegated authority to give a creditor a preference which could be deemed an unfair preference in accordance with section 604 of the Companies Act.

14. The obligations expressed to be assumed by each party to the Indenture are legal, valid, binding and
enforceable obligations under all applicable laws and in all applicable jurisdictions, other than, in the case of the Company, the laws of Ireland and the jurisdiction of Ireland.

15. If any obligation of any of the parties under the Indenture is to be performed in any jurisdiction other than
Ireland, its performance will not be illegal or ineffective by virtue of the laws of that jurisdiction and there are no provisions of the laws or public policy of any jurisdiction outside Ireland which would be contravened by the execution or
performance of the Indenture or which would render its performance ineffective by virtue of the laws of that jurisdiction.

16. The Indenture and the transactions contemplated thereby and the payments to be made thereunder are not and will
not be affected by any financial restrictions or sanctions arising from orders made by the Minister for Finance under the Financial Transfers Act 1992 of Ireland and/or section 42 of the Criminal Justice (Terrorist Offences) Act 2005 of Ireland or
the Criminal Justice (Money Laundering and Terrorist Financing) Act 2010 of Ireland.

17. All authorisations, approvals, licences, exemptions or consents of governmental or regulatory authorities with
respect to the agreements or arrangements referred to in the Registration Statement (including the prospectus contained therein and the Prospectus Supplement) or with respect to the issue, offer or sale of the Notes (other than, in the case of the
Company, the governmental or regulatory authorities of Ireland) have been obtained and are in full force and effect, the Notes will be issued in the form set out in the Indenture and the selling restrictions contained in the Registration Statement
(including the prospectus contained therein and the Prospectus Supplement) and the Underwriting Agreement have been and will, at all times, be observed and the Company will otherwise comply with the terms of any other lawful agreements relating to
the issue, sale and/or offer of the Notes.

18. The creation, issuance, offering and sale, including the marketing, of the Notes will be made, effected and
conducted in accordance with and will not otherwise violate any applicable laws and regulations of any jurisdiction, including Ireland, or supra-national authority, including, without limitation: (a) the securities laws and regulations of any
jurisdiction or supra-national authority which impose any restrictions, or mandatory requirements, in relation to the offering or sale of the Notes to the public in any jurisdiction, including the obligation to prepare a prospectus or registration
document relating to the Notes and (b) any requirement or restriction imposed by any court, governmental body or supra-national authority having jurisdiction over the Company or the members of its group.

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19. That: (a) the Company will be fully solvent at the time of and immediately following the issue of the
Notes, (b) no resolution or petition for the appointment of a liquidator or examiner will be passed or presented prior to the issue of the Notes, (c) no receiver will have been appointed in relation to any of the assets or undertaking of
the Company prior to the issue of the Notes and (d) no composition in satisfaction of debts, scheme of arrangement, or compromise or arrangement with creditors or members (or any class of creditors or members) will be proposed, sanctioned or
approved in relation to the Company prior to the issue of the Notes.

20. The information disclosed by the Searches was accurate and complete as of the date the Searches were made and
has not been altered, and the Searches did not fail to disclose any information which had been delivered for registration but which did not appear from the information available at the time the Searches were made or which ought to have been
delivered for registration at that time but had not been so delivered. No additional matters would have been disclosed by searches being carried out since that time.

21. No proceedings have been or will be instituted or injunction granted against the Company to restrain it from
guaranteeing the Notes and the guarantee by the Company of the Notes would not be contrary to any state, government, court, state or quasi-governmental agency, licencing authority, local or municipal government body or regulatory authority's
order, direction, guideline, recommendation, decision, licence or requirement.

22. The absence of fraud and the presence of good faith on the part of all parties to the Documents and their
respective officers, employees, agents and advisors.

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**Schedule 3** 

**Qualifications** 

The opinions in this Opinion are subject to the following qualifications:

1. A search at the Companies Registration Office is not conclusively capable of revealing whether or not a winding-up petition or a petition for the appointment of an examiner, receiver or liquidator has been presented or a resolution passed for the winding-up of the Company. A
search on the Index of Petitions and Winding-up Notices maintained at the Central Office of the High Court of Ireland is not capable of revealing whether or not a receiver has been appointed in respect of the
Company.

2. Whilst each of the making of a winding-up order or resolution, the
making of an order for the appointment of an examiner or the appointment of a receiver may be revealed by a search at the Companies Registration Office it may not be filed at the Companies Registration Office immediately and, therefore, our searches
at the Companies Registration Office may not have revealed such matters. Similarly whilst a petition to wind-up the Company may be revealed by a search on Index of Petitions and Winding-up Notices maintained at the Central Office of the High Court of Ireland, the making of a winding-up order may not be filed on the Index immediately and
therefore our searches may not have revealed such matters.

3. The position reflected in the Searches may not be fully up to date.

4. The expression "valid and binding" when used in this Opinion mean that the obligations expressed to
be assumed are of a type which the courts of Ireland will treat as valid and binding. It does not mean that these obligations will necessarily be enforced in all circumstances in accordance with their terms. In particular, enforcement of obligations
may be:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) limited by general principles of equity, in particular, equitable remedies (such as an order for specific
performance or an injunction) which are discretionary and are not available where damages are considered to be an adequate remedy;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) subject to any limitations arising from examinership, administration, bankruptcy, insolvency, moratoria,
receivership, liquidation, reorganisation, court scheme of arrangement, arrangement and similar laws affecting the rights of creditors;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) limited by the provisions of the laws of Ireland applicable to contracts held to have been frustrated by events
happening after their execution;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) invalidated if and to the extent that performance or observance arising in a jurisdiction outside Ireland would
be unlawful, unenforceable, or contrary to public policy or to the exchange control regulations under the laws of such jurisdiction;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e) invalidated by reason of fraud; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f) barred under the Statutes of Limitations of 1957 of Ireland (as amended from time to time) or may be or become
subject to the defence of set-off or counterclaim.

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5. The Companies Act prohibits certain steps being taken except with the leave of the court against a company
after the presentation of a petition for the appointment of an examiner. This prohibition continues if an examiner is appointed for so long as the examiner remains appointed (maximum period of one hundred days or such period as the court in question
may determine). Prohibited steps include steps taken to enforce any security over the company's property, the commencement or continuation of proceedings or execution or other legal process or the levying of distress against the company or its
property and the appointment of a receiver.

6. Under the provisions of the Companies Act, an examiner can be appointed on a petition to the Circuit Court, if
certain criteria are met. It is not possible for anyone other than a party to the relevant proceedings or the solicitors on record for such parties to inspect the Circuit Court files to ascertain whether a petition for the appointment of an examiner
has been made in the Circuit Court, and we have made no searches or enquiries in this regard in respect of the Company.

7. A contractual provision conferring or imposing a remedy or an obligation consequent upon default may not be
enforceable if it were construed by an Irish court as being a penalty, particularly if it involved enforcing an additional pecuniary remedy (such as a default or overdue interest) referable to such default and which does not constitute a genuine and
reasonable pre-estimate of the damage likely to be suffered as a result of the default in payment of the amount in question or the termination in question; further, recovery may be limited by laws requiring
mitigation of loss suffered.

8. An Irish court may not give effect to an indemnity given by any party to the extent it is in respect of legal
costs incurred by an unsuccessful litigator or to the extent that it is in respect of litigation costs which are not awarded by the court.

9. In the event of any proceedings being brought in an Irish court in respect of a monetary obligation expressed
to be payable in a currency other than euro, an Irish court would have the power to give a judgment to pay a currency other than euro but may decline to do so in its discretion and an Irish court might not enforce the benefit of currency conversion
or indemnity clauses and, with respect to a bankruptcy, liquidation, insolvency, reorganisation or similar proceeding, the laws of Ireland may require that all claims or debts be converted into euro at an exchange rate determined by the court as at
a date related thereto, such as the date of commencement of a winding-up.

10. This Opinion does not deal with the tax treatment of the issuance, transfer and guarantee of the Notes or any
payments in respect of the Notes and/or the guarantee of the Notes.

11. Where a party is vested with a discretion or may determine a matter in his or its opinion, the laws of Ireland
may require that such discretion is exercised reasonably or that such opinion is based upon reasonable grounds.

12. The courts of Ireland may interpret restrictively any provision purporting to allow the beneficiary of a
guarantee or other suretyship to make a material amendment to the obligations to which the guarantee or suretyship relates without further reference to the guarantor or surety.

13. An Irish court may not give effect to any provision of a contract which: (a) provides for a matter to be
determined by future agreement or negotiation or (b) it considers to be devoid of any meaning, vague or uncertain.

14. A right of set-off provided for in a contract or another document may
not be enforceable in all circumstances.