X0306 4 2021-03-01 0 0001501585 HUNTINGTON INGALLS INDUSTRIES, INC. HII 0001594313 Cuccias Brian J. 4101 WASHINGTON AVENUE NEWPORT NEWS VA 23607 0 1 0 0 Ex. VP & President, Ingalls Common Stock 2021-03-01 4 A 0 5274 178.41 A 62533.478 D Common Stock 2021-03-02 4 F 0 2379 178.41 D 60154.478 D SEP Unit Common Stock 78.36 332.809 D The Huntington Ingalls Industries, Inc. Compensation Committee determined that all performance goals had been met for these restricted stock units, and they were issued on March 1, 2021. The reporting person's interest in the HII Stock Fund of the Huntington Ingalls Industries, Inc. Savings 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/ Kathy S. Owen, Attorney-in-Fact for Brian J. Cuccias 2021-03-02