X0306 4 2022-05-12 0 0001819994 Rocket Lab USA, Inc. RKLB 0001671507 Kampani Arjun C/O ROCKET LAB USA, INC. 3881 MCGOWEN STREET LONG BEACH CA 90808 0 1 0 0 See Remarks Common Stock 2022-05-12 4 A 0 618956 0.00 A 618956 D Represents restricted stock units ("RSUs") granted to Mr. Kampani under the Rocket Lab USA, Inc. 2021 Stock Option and Incentive Plan (the "2021 Plan"). Such RSUs will vest as follows: 1/16 of the RSUs will vest on August 22, 2022 and 1/16 of the RSUs will vest on each March 1st, May 22nd, August 22nd or November 22nd thereafter, in each case subject to the reporting person's continuous service relationship through each applicable vesting date. The RSUs were granted on May 12, 2022. Senior Vice President, General Counsel and Secretary /s/ Arjun Kampani 2022-05-16