X0306 4 2015-06-04 0 0000866121 ORBITAL ATK, INC. OA 0001313857 Larson Blake E C/O ORBITAL ATK, INC. 45101 WARP DRIVE DULLES VA 20166 0 1 0 0 Chief Operating Officer Common Stock 2015-06-04 4 M 0 5000 48.8305 A 30087 D Common Stock 2015-06-04 4 S 0 5000 72.6915 D 25087 D Common Stock 19000 I By Family Trust Common Stock 631 I By Spousal Trust Common Stock 184 I By Family Trust Employee Stock Option (right to buy) 48.8305 2015-06-04 4 M 0 5000 0 D 2011-09-08 2015-09-08 Common Stock 5000 0 D 8,025 of these shares are subject to certain restrictions including possible forfeiture under Orbital ATK, Inc.'s (formerly Alliant Techsystems Inc.'s) 2005 Stock Incentive Plan. This is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $72.52 to $72.93, inclusive. The reporting person undertakes to provide Orbital ATK, Inc., any security holder of Orbital ATK, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. These shares are held in a family trust, of which the reporting person's spouse and children are the beneficiaries and the reporting person is the settlor and trustee. These shares are held in a trust of which the reporting person's spouse is the trustee and the reporting person is the beneficiary. These shares represent the reporting person's proportional interest as a beneficiary of a family trust. /s/Blake E. Larson 2015-06-05