X0306 4 2017-03-15 0000004281 Arconic Inc. ARNC 0001136562 PLANT JOHN C 390 PARK AVENUE NEW YORK, NY 10022 1 0 0 0 Phantom Stock Units 2017-03-15 4 J 0 832 27.26 D Common Stock 832 3557 D Each phantom stock unit is the economic equivalent of one share of Arconic common stock. Represents a partial reversal of transactions on April 1, 2016, July 1, 2016 and October 3, 2016, where an excess number of phantom stock units was acquired due to administrative errors in calculating applicable payment and crediting amounts. Phantom stock units are acquired under the Issuer's Amended and Restated Deferred Fee Plan for Directors and are to be paid out in cash after Board service ends. On October 5, 2016, the Issuer effected a 1-for-3 reverse stock split of its common stock (the "Reverse Stock Split"). The amount of securities reported on this Form 4 have been adjusted to reflect the Reverse Stock Split. On November 1, 2016, the Issuer completed the separation of its business into two independent, publicly-traded companies (the "Separation"): the Issuer and Alcoa Corporation. In connection with the Separation, and pursuant to the terms of an Employee Matters Agreement dated October 31, 2016, by and between the Issuer and Alcoa Corporation, all phantom stock units held by the reporting person with respect to the Issuer's common stock were adjusted in a manner intended to preserve the aggregate intrinsic value of the phantom stock units immediately prior to the Separation. The amount of securities reported on this Form 4 reflect the aforementioned adjustment. /s/ Margaret Lam (Assistant Secretary), by power of attorney 2017-03-17