Sec Form 4/A Filing - Evans John M. @ Beam Therapeutics Inc. - 2020-02-05

FORM 4/A 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 Evans John M. 2. Issuer Name and Ticker or Trading Symbol Beam Therapeutics Inc. [ BEAM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) CEO (Last) (First) (Middle) C/O BEAM THERAPEUTICS INC., 26 LANDSDOWNE STREET 3. Date of Earliest Transaction (MM/DD/YY) 02/05/2020 (Street) CAMBRIDGE, MA02139 4. If Amendment, Date Original Filed (MM/DD/YY) 08/17/2020 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 Stock Option (Right to Buy) ( 1 ) $ 0.67 02/05/2020 A 99,336 ( 2 )( 3 ) 05/08/2028 Common Stock 99,336 $ 0 99,336 D Stock Option (Right to Buy) ( 1 ) $ 4.22 02/05/2020 A 53,964 ( 4 ) 02/13/2029 Common Stock 53,964 $ 0 53,964 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Evans John M. C/O BEAM THERAPEUTICS INC. 26 LANDSDOWNE STREET CAMBRIDGE, MA02139 X CEO Signatures By: /s/ Christine Bellon, Attorney-in-fact 09/21/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On August 17, 2020, the reporting person filed a Form 4 which inadvertently omitted certain options held by the reporting person on such date (the "Original Form 4"). ( 2 )On May 8, 2018, the reporting person was granted an option to purchase 198,672 shares of common stock of Beam Therapeutics Inc. (the "Company"). The option award vests (i) fifty percent (50%) upon the Company achieving a certain development milestone related to base editing applications, and (ii) fifty percent (50%) upon the achievement of a closing price hurdle following the Company's initial public offering ("IPO") (which closing price hurdle has been achieved) (the "Price Condition"). The portion of the award subject to satisfaction of the Price Condition is scheduled to vest in three equal installments on December 21, 2021, June 30, 2022 and December 31, 2022. Upon the closing of the IPO, vesting of the portion of the option award subject to condition (ii) was tied only to the passage of time and the market price of the Company's securities and thus, 50% of the option award became reportable. ( 3 )(Continued from Footnote 2) The Original Form 4 failed to report the portion of the option award that became reportable upon the closing of the Company's IPO. ( 4 )On February 13, 2019, the reporting person was granted an option to purchase 107,929 shares of common stock of the Company. The option award vests (i) fifty percent (50%) upon the Company achieving a certain development milestone related to base editing applications, and (ii) fifty percent (50%) upon the achievement of a closing price hurdle following the Company's IPO (which closing price hurdle has been achieved). The portion of the award subject to satisfaction of the Price Condition is scheduled to vest in three equal installments on December 21, 2021, June 30, 2022 and December 31, 2022. Upon the closing of the IPO, vesting of the portion of the option award subject to condition (ii) was tied only to the passage of time and the market price of the Company's securities and thus, 50% of the option award became reportable. The Original Form 4 failed to report the portion of the option award that became reportable upon the closing of the Company's IPO.

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).

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