X0508 4 2026-02-24 0 0001501585 HUNTINGTON INGALLS INDUSTRIES, INC. HII 0001651056 Schuck Nicolas G 4101 WASHINGTON AVENUE NEWPORT NEWS VA 23607 0 1 0 0 Corp VP, Controller & CAO 0 Common Stock 2026-02-24 4 M 0 271.852 0 A 2690.303 D Common Stock 2026-02-24 4 F 0 136.852 447.73 D 2553.451 D Restricted Stock Rights 2026-02-24 4 M 0 271.852 0 D Common Stock 271.852 851.501 D SEP Common Stock 1216.4 5253.0069 D Shares withheld by issuer for the payment of withholding taxes on Restricted Stock Rights ("RSRs") that vested on February 24, 2026. Each RSR represents a contingent right to receive an equivalent number of shares of Company common stock, or, at the discretion of the Company's Compensation Committee, cash or a combination of cash and Company common stock. The RSRs were granted under the 2022 Long-Term Incentive Stock Plan ("LTISP") on 2/24/25 and vest ratably in three equal installments upon each of the first, second and third anniversaries of the grant date. The reporting person's interest in the HII Stock Fund of the Huntington Ingalls Industries, Inc. Savings Excess Plan (the "Plan") is held in the form of units of interest. The Plan's administrator calculates the number of shares of issuer common stock represented by units in the HII Stock Fund. /s/ Tiffany M. King, Attorney-in-Fact 2026-02-25