X0306 4 2020-02-24 0 0001018963 ALLEGHENY TECHNOLOGIES INC ATI 0001572385 WETHERBEE ROBERT S 1000 SIX PPG PLACE PITTSBURGH PA 15222 0 1 0 0 President and CEO Common Stock, $0.10 par value per share 2020-02-24 4 A 0 48738 0.00 A 160288.3409 D Common Stock, $0.10 par value per share 2020-02-24 4 F 0 22167 19.44 D 138121.3409 D Common Stock, $0.10 par value per share 2020-02-24 4 F 0 2387 19.44 D 135734.3409 D Common Stock, $0.10 par value per share 2020-02-24 4 A 0 61728 0.00 A 197462.3409 D Settlement of performance-vested restricted stock units that were granted in 2017, the vesting of which was contingent upon the Issuer's achievement of specified performance criteria during the period form January 1, 2017 through December 31, 2019 (the "2017-2019 PSUs"). The shares underlying the 2017-2019 PSUs became payable as of February 24, 2020 following certification of the Issuer's achievement of such performance criteria by the Personnel and Compensation Committee of the Issuer's Board of Directors. Shares withheld for payment of taxes in connection with the February 24, 2020 settlement of the 2017-2019 PSUs. 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 February 24, 2020. Shares withheld for payment of taxes on restricted stock units awarded on February 23, 2017. One-third of such restricted stock units vested by their terms on February 24, 2020. Award of restricted stock units, which are settled in shares of stock upon vesting. The award vests in three equal annual installments on each of the first three anniversaries of the grant date. /s/ Elliot S. Davis, Attorney-in-Fact for Robert S. Wetherbee 2020-02-26