X0306 4 2023-01-10 0 0001492426 Horizon Therapeutics Public Ltd Co HZNP 0001230482 SHERMAN JEFFREY W C/O HORIZON THERAPEUTICS PLC, 70 ST. STEPHEN?S GREEN DUBLIN L2 D02 E2X4 IRELAND 0 1 0 0 EVP and Chief Medical Officer Ordinary Shares 2023-01-10 4 S 0 3368 113.05 D 39539 D Ordinary Shares 2023-01-11 4 S 0 3368 113.10 D 36171 D Ordinary Shares 49314 I See Footnote Ordinary Shares 84430 I See Footnote Ordinary Shares 66730 I by Spouse The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 11, 2022. The shares are held in the Jeffrey W. Sherman Living Trust. The shares are held in the name of the Jeffrey W. Sherman 2020 Gift Trust, of which the reporting person's spouse is the Trustee. /s/ Patrick McIlvenny, Attorney-in-Fact 2023-01-12