Sec Form 3 Filing - Simon Amy @ Beam Therapeutics Inc. - 2023-03-16

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

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1. Name and Address of Reporting Person Simon Amy 2. Issuer Name and Ticker or Trading Symbol Beam Therapeutics Inc. [ BEAM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Medical Officer (Last) (First) (Middle) C/O BEAM THERAPEUTICS INC., 238 MAIN STREET 3. Date of Earliest Transaction (MM/DD/YY) 03/16/2023 (Street) CAMBRIDGE, MA02142 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 Common Stock 65,129 ( 1 ) ( 2 ) D

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 Stock Option (Right to Buy) $ 80.04 ( 3 ) 03/31/2031 Common Stock 79,500 D Stock Option (Right to Buy) $ 69.21 ( 4 ) 01/31/2032 Common Stock 30,000 D Stock Option (Right to Buy) $ 38.71 ( 5 ) 06/30/2032 Common Stock 10,000 D Stock Option (Right to Buy) $ 43.45 ( 6 ) 01/31/2033 Common Stock 40,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Simon Amy C/O BEAM THERAPEUTICS INC. 238 MAIN STREET CAMBRIDGE, MA02142 Chief Medical Officer Signatures By: /s/ Christine Bellon, Attorney-in-Fact 03/27/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Includes 44,813, 15,000 and 5,000 restricted stock units ("RSUs") granted to the Reporting Person under the Issuer's 2019 Equity Incentive Plan on March 31, 2021, March 31, 2022 and June 30, 2022 respectively. ( 2 )Each RSU represents the contingent right to receive one share of the Issuer's common stock. The RSUs vest in four substantially equal installments on each of the first four anniversaries of the date of grant, subject to the Reporting Person's continued service with the Issuer through each vesting date. The March 31, 2021 RSUs grant was originally for 59,750 RSUs of which 14,937 RSUs have already vested. ( 3 )The option vests as to 25% on the first anniversary of the vesting commencement date, March 31, 2022, and at a rate of 2.78% each month thereafter until the option is fully vested. ( 4 )The option vests at a rate of 2.08% each month after January 31, 2022 until the option is fully vested. ( 5 )The option vests at a rate of 2.08% each month after June 30, 2022 until the option is fully vested. ( 6 )The option vests at a rate of 2.08% each month after January 31, 2022 until the option is fully vested.

Remarks: Exhibit List: Exhibit 24 - Power of Attorney

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