Sec Form 3 Filing - Hankamer Brittany @ Avantor, Inc. - 2023-08-23

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 Hankamer Brittany 2. Issuer Name and Ticker or Trading Symbol Avantor, Inc. [ AVTR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) EVP, Chief HR Officer (Last) (First) (Middle) RADNOR CORPORATE CENTER, BUILDING ONE,, SUITE 200, 100 MATSONFORD ROAD 3. Date of Earliest Transaction (MM/DD/YY) 08/23/2023 (Street) RADNOR, PA19087 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 25,498 ( 1 ) 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 Options (Right to Buy) $ 17.26 ( 2 ) 09/03/2029 Common Stock 47,043 D Stock Options (Right to Buy) $ 17.67 ( 3 ) 02/20/2030 Common Stock 37,637 D Stock Options (Right to Buy) $ 27.64 ( 4 ) 02/25/2031 Common Stock 16,101 D Stock Options (Right to Buy) $ 33.09 ( 5 ) 02/23/2032 Common Stock 16,390 D Stock Options (Right to Buy) $ 24.62 ( 6 ) 02/24/2033 Common Stock 14,274 D Stock Options (Right to Buy) $ 21.12 ( 7 ) 08/14/2033 Common Stock 7,022 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Hankamer Brittany RADNOR CORPORATE CENTER, BUILDING ONE, SUITE 200, 100 MATSONFORD ROAD RADNOR, PA19087 EVP, Chief HR Officer Signatures /s/ Scott K. Baker, as Attorney-in-Fact 08/24/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Includes i) 1,268 Restricted Stock Units that vest on September 3, 2023; ii) 972 Restricted Stock Units that vest annually on February 20, through the year 2024; iii) 2,488 Restricted Stock Units that vest annually on February 21, through the year 2025; iv) 4,250 Restricted Stock Units that vest annually on February 23, through the year 2026; v) 5,889 Restricted Stock Units that vest annually on February 24, through the year 2027; and vi) 2959 Restricted Stock Units that vest annually on August 14, through the year 2027. ( 2 )Reflects options that vest in four equal annual installments beginning on September 3, 2020. ( 3 )Reflects options that vest in four equal annual installments beginning on February 20, 2021. ( 4 )Reflects options that vest in four equal annual installments beginning on February 25, 2022. ( 5 )Reflects options that vest in four equal annual installments beginning on February 23, 2023. ( 6 )Reflects options that vest in four equal annual installments beginning on February 24, 2024. ( 7 )Reflects options that vest in four equal annual installments beginning on August 14, 2024.

Remarks: Exhibit List: 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).

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