X0306 4/A 2020-04-02 2020-04-06 0000004281 Howmet Aerospace Inc. HWM 0001136562 PLANT JOHN C 201 ISABELLA STREET SUITE 200 PITTSBURGH, PA 15212-5872 1 1 0 0 Co-Chief Executive Officer Restricted Stock Unit 2020-04-02 4 A 0 1000000 0 A Common Stock 1000000 1729998 D Restricted Stock Unit 2020-04-02 4 A 0 1800000 0 A Common Stock 1800000 3529998 D Each restricted stock unit represents a contingent right to receive one share of common stock of Howmet Aerospace Inc. (Howmet) or, at as elected by Howmet, a cash equivalent to the fair market value thereof. The restricted stock units will vest in three equal installments on March 31, 2021, March 31, 2022 and March 31, 2023, respectively, and subject to the continued employment of the reporting person through the applicable vesting date. These restricted stock units vest in full or in part on March 31, 2023, and are contingent on the continuing service of Mr. Plant as Co-Chief Executive Officer through such date and the achievement of certain performance goals relating to the stock price of Howmet and subject to partial or full accelerated vesting upon the occurrence of certain events. Vested restricted stock units will be settled in shares or cash, as applicable, within 30 days following the vesting date. On April 1, 2020, Arconic Inc. completed the separation of its business into two independent, publicly-traded companies (the Separation): Howmet Aerospace Inc. and Arconic Corporation. This Form 4 is being amended to reflect the total number of Howmet Aerospace Inc. shares underlying equity awards held by the reporting person after reflecting the adjustment of all Arconic Inc. equity awards held by the reporting person as of the Separation to relate to Howmet Aerospace Inc. common stock in a manner intended to preserve the aggregate intrinsic value of the original awards, in accordance with the Employee Matters Agreement, as amended, between Howmet Aerospace Inc. and Arconic Corporation. /s/ Margaret Lam (Assistant Secretary), by power of attorney 2020-04-24