X0306 4 2017-05-31 0 0000866121 ORBITAL ATK, INC. OA 0001514429 Wolf Christine Ann C/O ORBITAL ATK, INC. 45101 WARP DRIVE DULLES VA 20166 0 1 0 0 Senior VP Human Resources Common Stock 2017-05-31 4 M 0 5039 26.2528 A 21867 D Common Stock 2017-05-31 4 S 0 5039 101.5438 D 16828 D Employee Stock Option (right to buy) 26.2528 2017-05-31 4 M 0 5039 0 D 2022-03-06 Common Stock 5039 0 D 3,794 of these shares are subject to certain restrictions including possible forfeiture under the Issuer's stock incentive plans. This is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $101.41 to $101.69, 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. Options became exercisable in three equal annual installments beginning March 6, 2013. /s/ Richard N. Osborne, Attorney-in-Fact 2017-06-01