Name of person dealing (Note 1)

TIAA-CREF Investment Management, LLC/Teachers Advisors, LLC/Nuveen Asset Management, LLC

Company dealt in

HORIZON THERAPEUTICS PLC

Class of relevant security to which the dealings being disclosed relate (Note 2)

$0.0001Ordinary Shares

Date of dealing

31 January 2023

Long

Short

Number

(%)

Number

(%)

(1) Relevant securities

3,191,755 1.395%

(2) Derivatives (other than options)

(3) Options and agreements to purchase/sell

Total

3,191,755 1.395%

Class of relevant security:

Long

Short

Number

(%)

Number

(%)

(1) Relevant securities

N/A

N/A

(2) Derivatives (other than options)

N/A

N/A

(3) Options and agreements to purchase/sell

N/A

N/A

Total

Purchase/sale

Number of relevant securities

Price per unit (Note 5)

Sell

192,047

109.801

Buy

1,152

109.720

Product name,

e.g. CFD

Nature of transaction

(Note 6)

Number of relevant securities

(Note 7)

Price per unit

(Note 5)

N/A

N/A

N/A

N/A

Product name,

e.g. call option

Writing, selling, purchasing, varying etc.

Number of securities to which the option relates (Note 7)

Exercise price

Type, e.g. American, European etc.

Expiry date

Option money paid/received per unit (Note 5)

N/A

N/A

N/A

N/A

N/A

N/A

N/A

Product name,

e.g. call option

Number of securities

Exercise price per unit (Note 5)

N/A

N/A

N/A

Nature of transaction

(Note 8)

Details

Price per unit

(if applicable) (Note 5)

N/A

N/A

N/A

Date of disclosure

01 February 2023

Contact name

Stuart R. Brunet

Telephone number

+1 (415) 882-3711

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

N/A

If a connected EFM, state nature of connection (Note 10)

N/A