Sec Form 3 Filing - Spice Adam C. @ Rocket Lab USA, Inc. - 2021-08-25

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Spice Adam C. 2. Issuer Name and Ticker or Trading Symbol Rocket Lab USA, Inc. [ RKLB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Financial Officer (Last) (First) (Middle) C/O ROCKET LAB USA, INC., 3881 MCGOWEN STREET 3. Date of Earliest Transaction (MM/DD/YY) 08/25/2021 (Street) LONG BEACH, CA90808 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Employee Stock Option (right to buy) $ 1.09 ( 1 ) 08/03/2028 Common Stock 5,121,651 D Earnout Rights (option) ( 2 ) ( 2 ) ( 2 ) Common Stock 413,876 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Spice Adam C. C/O ROCKET LAB USA, INC. 3881 MCGOWEN STREET LONG BEACH, CA90808 Chief Financial Officer Signatures /s/ Robert M.P. Hurwitz, as Attorney-in-Fact for Adam C. Spice 09/07/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The stock option was granted on August 3, 2018, and had a vesting commencement date of May 25, 2018. 1/4 of the shares subject to the stock option vest on the one year anniversary of the vesting commencement date, and 1/48 of the shares subject to the stock option vest on a monthly basis each month thereafter, subject, in each case, to the reporting person's continued service relationship through each applicable vesting date. ( 2 )Each earnout right represents a contingent right (based on the reporting person's ownership of stock options) to receive one share of the issuer's common stock. The earnout rights vest upon the issuer's common stock achieving a closing price per share equal to or greater than $20.00 for a period of at least 20 trading days out of 30 consecutive trading days during the period commencing on the 90th day following August 25, 2021 and ending on the 180th day following August 25, 2021. If the earnout rights vest, the reporting person's stock option will be adjusted to relate to an additional number of shares of the issuer's common stock equal to the number of earnout rights that vest, with no corresponding adjustment to the aggregate exercise price of such option. If the target closing stock price is not achieved during such period, the earnout rights will be forfeited.

Remarks: Exhibit 24 - Power of Attorney

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.