X0306 4 2019-05-10 0 0001018963 ALLEGHENY TECHNOLOGIES INC ATI 0001241243 HARVEY J BRETT 1000 SIX PPG PLACE PITTSBURGH PA 15222 1 0 0 0 Common Stock, par value $0.10 per share 2019-05-10 4 F 0 56 23.72 D 42599.815 D Common Stock, par value $0.10 per share 2019-05-13 4 A 0 7145 0.00 A 49744.815 D Common Stock, par value $0.10 per share 2019-05-14 4 F 0 46 22.74 D 49698.815 D Shares withheld for payment of taxes in connection with the May 10, 2019 vesting of restricted stock granted in May 2016. Represents the average of the high and low trading prices for one share of the Issuer's common stock on the New York Stock Exchange on May 10, 2019. Annual Director award under the Issuer's 2017 Incentive Plan as part of the Issuer's Director compensation program. Includes 4,397 shares representing Mr. Harvey's annual director award and 2,748 shares that Mr. Harvey elected to receive in lieu of a portion of his 2019 cash retainer. Shares withheld for payment of taxes in connection with the May 14, 2019 vesting of restricted stock granted in May 2018. Represents the average of the high and low trading prices for one share of the Issuer's common stock on the New York Stock Exchange on May 14, 2019. /s/ Elliot S. Davis, Attorney-in-Fact for J. Brett Harvey 2019-05-14