X0306 4 2021-02-17 0 0000030305 DUCOMMUN INC /DE/ DCO 0001695904 Oswald Stephen G 200 SANDPOINTE AVENUE SUITE 700 SANTA ANA CA 92707-5759 1 1 0 0 Chairman, President & CEO Common Stock 2021-02-17 4 A 0 61250 0.00 A 265872 D Common Stock 2021-02-17 4 F 0 32249 55.51 D 233623 D Common Stock 2021-02-17 4 A 0 18000 0.00 A 251623 D Acquired upon the settlement of performance stock units granted on March 18, 2018 under the Ducommun Incorporated Stock Incentive Plan as a result of the satisfaction of the performance criteria underlying the award. Granted as compensation for services. The total amount of securities listed includes 695 shares of common stock acquired on January 31, 2021 through the Ducommun Incorporated Employee Stock Purchase Plan. Represents a reduction in shares to satisfy the tax withholding obligations of the Issuer with respect to the settlement, on February 17, 2021, of 61,250 performance stock units, as described in footnote (1) above. Stephen G. Oswald 2021-02-19