Timothy P. Walbert - 06 Oct 2023 Form 4 Insider Report for Horizon Therapeutics Public Ltd Co

Footnote F1

Includes 279 Ordinary Shares (as defined in footnote 2 of this Form 4) acquired by the reporting person on June 1, 2023 pursuant to an employee stock purchase program.

Footnote F2

Reflects the disposition of ordinary shares of Horizon Therapeutics plc ("Issuer"), nominal value $0.0001 per share ("Ordinary Shares"), in connection with the consummation of the transactions contemplated by the Transaction Agreement (the "Transaction Agreement"), dated as of December 11, 2022, by and among Issuer, Amgen Inc. ("Parent"), and Pillartree Limited, a wholly owned subsidiary of Parent ("Acquirer Sub"), including the consummation of a scheme of arrangement under Chapter 1 of Part 9 of the Companies Act 2014 of Ireland (the "Scheme") pursuant to which Acquirer Sub acquired Issuer. Pursuant to the Transaction Agreement, on October 6, 2023, the effective time of the Scheme (the "Effective Time"), each outstanding Ordinary Share was converted into $116.50 in cash (the "Consideration").

Footnote F3

The Ordinary Shares are held by the Timothy P. Walbert 2021 Gift Trust, of which the Reporting Person's spouse is the Trustee and beneficiary.

Footnote F4

The Ordinary Shares are held by the Keli B. Walbert 2021 Gift Trust, of which the Reporting Person is the Trustee. The beneficiaries of the Trust include the Reporting Person and his descendants.

Footnote F5

The Option (as defined in footnote 6 to this Form 4) is fully vested.

Footnote F6

Reflects the disposition of Issuer's options to purchase Ordinary Shares (each, an "Option") as contemplated by the Transaction Agreement. Pursuant to the Transaction Agreement, at the Effective Time, each outstanding Option (whether or not vested) was canceled and converted into the right to receive cash, without interest, in an amount equal to (a) the total number of Ordinary Shares subject to such Option, multiplied by (b) the excess of (i) the Consideration over (ii) the exercise price payable per Ordinary Share under such Option.

Footnote F7

Each RSU (as defined in footnote 9 to this Form 4) and PSU (as defined in footnote 13 to this Form 4) represents a contingent right to receive one Ordinary Share of the Issuer.

Footnote F8

The Ordinary Shares subject to the RSUs vest on January 5, 2024.

Footnote F9

Reflects the disposition of Issuer's restricted stock unit awards, excluding PSUs (as defined in footnote 14 to this Form 4), (each, a "RSU") as contemplated by the Transaction Agreement. Pursuant to the Transaction Agreement, at the Effective Time, each outstanding RSU (whether or not vested) was assumed and converted into a restricted stock unit (each, a "Parent RSU") denominated in shares of Parent's common stock. The number of shares of Parent's common stock subject to each such Parent RSU was equal to the product (rounded down to the nearest whole number) of (y) the number of shares of Ordinary Shares subject to the RSU immediately prior to the Effective Time multiplied by (z) the ratio equal to (1) the Consideration divided by (2) the volume weighted average of the per share closing price of Parent's common stock on the Nasdaq for five (5) trading days ending on the second business day prior to the completion of the Scheme.

Footnote F10

The Ordinary Shares subject to the RSUs vest 1/3rd annually on each anniversary of January 5, 2022.

Footnote F11

The Ordinary Shares subject to the RSUs vest 1/3rd annually on each anniversary of January 5, 2023.

Footnote F12

The Ordinary Shares subject to the PSUs (as defined in footnote 13 to this Form 4) vest on January 5, 2024.

Footnote F13

Reflects the disposition of Issuer's restricted stock unit awards with performance-based vesting or delivery requirements (each, a "PSU") as contemplated by the Transaction Agreement. Pursuant to the Transaction Agreement, at the Effective Time, each outstanding PSU (whether or not vested) was canceled and converted into the right to receive cash, without interest, in an amount equal to (i) the total number of Ordinary Shares issuable in settlement of such PSU (as determined in accordance with the Transaction Agreement) multiplied by (ii) the Consideration.

Footnote F14

The Ordinary Shares subject to the PSUs vest 2/3rd on January 5, 2024 and the remaining shares vest on January 5, 2025.

Footnote F15

The Ordinary Shares subject to the PSUs vest on January 5, 2025.

Footnote F16

The Ordinary Shares subject to the PSUs vest on January 5, 2026.

Footnote F17

The Ordinary Shares subject to the PSUs vest 2/3rd on January 5, 2025 and the remaining shares vest on January 5, 2026.