X0306 4/A 2015-02-09 2015-02-11 0 0000866121 ORBITAL ATK, INC. OA 0001045853 THOMPSON DAVID W C/O ORBITAL ATK, INC. 45101 WARP DRIVE DULLES VA 20166 1 1 0 0 President and CEO Common Stock 2015-02-09 4 A 0 101232 A 101232 D Common Stock 2015-02-09 4 A 0 7272 A 7272 I By Trust The Form 4 originally filed to report this transaction has been amended for the purpose of reflecting that 7,272 of the shares of common stock previously included in this total as acquired and owned directly by the reporting person were actually acquired by the reporting person's trust. Represents 43,635 shares of common stock acquired pursuant to the Transaction Agreement among Alliant Techsystems, Inc. (renamed Orbital ATK, Inc.) ("Orbital ATK"), Vista Merger Sub Inc., Vista Outdoor Inc. (formerly known as Vista SpinCo Inc.) and Orbital Sciences Corporation ("Orbital") (the "Transaction Agreement"), pursuant to which each share of Orbital common stock was converted into 0.449 shares of Orbital ATK common stock and cash payable in lieu of fractional shares of Orbital ATK common stock; and 57,597 Restricted Stock Units acquired pursuant to the Transaction Agreement whereby each Restricted Stock Unit of Orbital was converted into 0.449 Restricted Stock Units of Orbital ATK with the same vesting schedule. The market value of Orbital ATK common stock was $63.94 per share based on the opening price per share of Orbital ATK common stock on the first day of trading following the Merger (as defined in the Transaction Agreement). The original Form 4 included these shares in the line item above. Acquired pursuant to the Transaction Agreement, pursuant to which each share of Orbital common stock was converted into 0.449 shares of Orbital ATK common stock and cash payable in lieu of fractional shares of Orbital ATK common stock. The market value of Orbital ATK common stock was $63.94 per share based on the opening price per share of Orbital ATK common stock on the first day of trading following the Merger (as defined in the Transaction Agreement). /s/ Richard N. Osborne, Attorney-in-Fact 2015-12-17