Form 8.3 - AON plc

1.

KEY INFORMATION

Name of person dealing

Massachusetts Financial Services Company

Company dealt in

AON PLC

Class of relevant security to which the

dealings being disclosed relate

Class A Ordinary Shares (IE00BLP1HW54)

Date of dealing

26 February 2021

2.

INTERESTS AND SHORT POSITIONS

(a)

Interests and short positions (following dealing) in the class of relevant security

dealt in

Long

Short

Number

(%)

Number

(%)

(1)

Relevant securities

19,738,342 shares

8.73 %

(2)

Derivatives (other than options):

(3)

Options and agreements to purchase/sell:

Total

19,738,342 shares

8.73 %

(b)

Interests and short positions in relevant securities of the company, other than the

class dealt in

Class of relevant security:

Long

Short

Number

(%)

Number

(%)

(1)

Relevant securities

(2)

Derivatives (other than options):

(3)

Options and agreements to purchase/sell:

Total

3.

DEALINGS

(a)

Purchases and sales

Purchase/sale

Number of relevant securities

Price per unit

In Kind Received

203 shares

230.9600 USD

In Kind Received

205 shares

227.7100 USD

Purchase

7,095 shares

229.9166 USD

Purchase

1,463 shares

229.0888 USD

Sale

65 shares

227.7100 USD

Sale

481 shares

230.2748 USD

Sale

630 shares

229.5011 USD

Sale

1,018 shares

228.6675 USD

Sale

2,485 shares

228.6032 USD

Sale

2,927 shares

228.1643 USD

(b)

Derivatives transactions (other than options transactions)

Product name

e.g. CFD

Nature of transaction

Number of relevant securities

Price per unit

(c)

Options transactions in respect of existing relevant securities

(i)

Writing, selling, purchasing or varying

Product name e.g. call option

Writing, purchasing, selling, varying etc.

Number of securities to which the option relates

Exercise price

Type, e.g. American, European etc.

Expiry date

Option money paid/ received per unit

(ii)

Exercising

Product name

e.g. call option

Number of securities

Exercise price per unit

(d)

Other dealings (including subscribing for new securities)

Nature of transaction

Details

Price per unit (if applicable)

4.

OTHER INFORMATION

Agreements, arrangements or understandings relating to options or derivatives

Full details of any agreement, arrangement or understanding between the person disclosing and any other person relating to the voting rights of any relevant securities under any option referred to on this form or relating to the voting rights or future acquisition or disposal of any relevant securities to which any derivative referred to on this form is referenced. If none, this should be stated.

None

Is a Supplemental Form 8 attached?

NO

Date of disclosure

01 March 2021

Contact name

Robert R. Flaherty

Telephone number

617-954-5814

If a connected EFM, name of offeree/offeror with which connected

If a connected EFM, state nature of connection