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

14 October 2020

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

20,604,461 shares

8.89 %

(2)

Derivatives (other than options):

(3)

Options and agreements to purchase/sell:

Total

20,604,461 shares

8.89 %

(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

167 shares

210.0900 USD

In Kind Delivered

7 shares

210.8900 USD

Purchase

9,786 shares

210.0900 USD

Sale

61 shares

210.0900 USD

Sale

2,232 shares

210.6882 USD

Sale

3,849 shares

210.6400 USD

Sale

5,000 shares

211.3500 USD

Sale

5,526 shares

212.6660 USD

Sale

26,151 shares

211.9117 USD

Sale

36,000 shares

211.6483 USD

Sale

61,600 shares

211.2426 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

15 October 2020

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