Sec Form 4 Filing - Stern Sadie @ DEXCOM INC - 2024-01-12

FORM 4 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 Stern Sadie 2. Issuer Name and Ticker or Trading Symbol DEXCOM INC [ DXCM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) EVP Chief Human Resources (Last) (First) (Middle) 6340 SEQUENCE DRIVE 3. Date of Earliest Transaction (MM/DD/YY) 01/12/2024 (Street) SAN DIEGO, CA92121 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 01/12/2024 A( 1 ) 7,620 ( 1 ) A $ 0.001 81,953 ( 2 ) D Common Stock 01/16/2024 S 2,902 ( 3 ) D $ 123.6348 79,051 ( 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 Sh ares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Stern Sadie 6340 SEQUENCE DRIVE SAN DIEGO, CA92121 EVP Chief Human Resources Signatures By: /s/ Jereme M Sylvain For: Sadie Stern 01/17/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents performance stock units ("PSUs") granted to the reporting person on March 8, 2021 that vested on January 12, 2024. ( 2 )Included in this number are 54,953 unvested restricted stock units, 21,769 of which were granted on March 8, 2023 and shall vest through March 8, 2026, 14,124 of which were granted on March 8, 2022 and shall vest through March 8, 2025, 3,340 of which were granted on December 15, 2021 and shall vest through December 15, 2024, 7,512 of which were granted on March 8, 2021 and shall vest through March 8, 2024, 8,208 of which were granted on November 19, 2020 and shall vest through November 19, 2024. ( 3 )Represents the number of shares required to be sold by the reporting person to cover tax withholding obligations in connection with the vesting of PSUs. This sale is mandated by the Issuer's election under its equity incentive plans to require the satisfaction of tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary trade by the reporting person.

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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