X0306 4 2022-01-04 0 0001492426 Horizon Therapeutics Public Ltd Co HZNP 0001792746 Pasternak Andy C/O HORIZON THERAPEUTICS PLC, 70 SAINT STEPHEN?S GREEN DUBLIN L2 D02 E2X4 IRELAND 0 1 0 0 EVP and Chief Business Officer Ordinary Shares 2022-01-05 4 M 0 48839 A 70669 D Ordinary Shares 2022-01-05 4 F 0 21710 101.84 D 48959 D Ordinary Shares 2022-01-06 4 S 0 500 97.30 D 48459 D Ordinary Shares 2022-01-06 4 S 0 700 98.33 D 47759 D Ordinary Shares 2022-01-06 4 S 0 6438 99.85 D 41321 D Ordinary Shares 2022-01-06 4 S 0 349 100.23 D 40972 D Restricted Stock Units (RSU) 2022-01-04 4 A 0 23805 0.00 A Ordinary Shares 23805 23805 D Restricted Stock Units (RSU) 2022-01-05 4 M 0 14514 0.00 D Ordinary Shares 14514 14514 D Restricted Stock Units (RSU) 2022-01-05 4 M 0 11642 0.00 D Ordinary Shares 11642 23286 D Restricted Stock Units (RSU) 2022-01-05 4 M 0 11067 0.00 D Ordinary Shares 11067 11069 D Restricted Stock Units (RSU) 2022-01-05 4 M 0 11616 0.00 D Ordinary Shares 11616 5800 D Each RSU represents a contingent right to receive one ordinary share of the Issuer. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 9, 2021. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $96.83 to $97.65 per share, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $97.95 to $98.79 per share, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $98.99 to $99.95 per share, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $100.05 to $100.62 per share, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The RSU's vest 1/3rd annually on each anniversary of January 5, 2022. The RSU's vest 1/3rd annually on each anniversary of January 5, 2021. 50% of the shares subject to the RSU's vested on 1/5/2022, and the remaining shares vest on 1/5/2023. Two-thirds of the ordinary shares subject to the RSUs vest on January 5, 2022 and the remaining one-third of the ordinary shares vest on January 5, 2023. /s/ Miles W. McHugh, Attorney-in-Fact 2022-01-06