[Form 4] DexCom, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Sadie Stern, EVP and Chief HR Officer of DexCom, Inc. (DXCM), reported a sale of common stock under a pre-established plan. On 09/04/2025 Ms. Stern disposed of 1,466 shares at $80.00 per share pursuant to a 10b5-1 trading plan adopted on 02/20/2025 to allow orderly dispositions. After the reported sale she beneficially owns 105,223 shares in total. That total includes 74,450 unvested restricted stock units with detailed vesting: 29,922 RSUs granted 03/08/2025 vesting through 03/08/2028; 22,798 RSUs granted 03/08/2025 vesting through 03/08/2027; 14,474 RSUs granted 03/08/2024 vesting through 03/08/2027; and 7,256 RSUs granted 03/08/2023 vesting through 03/08/2026. The Form 4 was signed by an attorney-in-fact on 09/08/2025.

Positive

• Sale executed under a 10b5-1 plan, indicating an established, pre-authorized trading arrangement
• Detailed disclosure of unvested RSUs with grant dates and vesting schedules, improving transparency

Negative

• Insider disposition of shares (1,466 shares sold), which reduces insider-held free shares
• Significant portion of holdings are unvested (74,450 RSUs), limiting current voting/transferable shares

Insights

Financial Analyst

TL;DR: Insider sale under a 10b5-1 plan; modest disposition relative to disclosed holdings.

The filing documents a scheduled sale of 1,466 shares at $80 executed under a 10b5-1 plan established 02/20/2025. The report shows total beneficial ownership of 105,223 shares, including 74,450 unvested RSUs with multi-year vesting schedules. This is a routine disclosure that confirms use of an affirmative-defense plan to transact shares and provides clarity on unvested equity outstanding to the executive.

Corporate Governance Expert

TL;DR: Governance practice observed—insider used a documented trading plan to avoid timing concerns.

The Form 4 explicitly notes the 10b5-1 plan adoption and that the reported sale was executed pursuant to that plan. The filing lists detailed vesting tranches for RSUs, which helps stakeholders understand potential future dilution and insider alignment. The signature by an attorney-in-fact is properly indicated. No other governance irregularities are reported in this filing.

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Stern Sadie

(Last) (First) (Middle)

6340 SEQUENCE DRIVE

(Street)

SAN DIEGO CA 92121

(City) (State) (Zip)

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 HR Officer

3. Date of Earliest Transaction (Month/Day/Year)
09/04/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	09/04/2025		S		1,466(1)	D	$80	105,223(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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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

Explanation of Responses:

1. On February 20, 2025, Ms. Stern adopted a 10b5-1 Plan. This 10b5-1 Plan allows the orderly disposition of shares owned by Ms. Stern. The shares set forth above were sold pursuant to the 10b5-1 Plan.

2. Included in this number are 74,450 unvested restricted stock units, 29,922 of which were granted on March 8, 2025 and shall vest through March 8, 2028, 22,798 of which were granted on March 8, 2025 and shall vest through March 8, 2027, 14,474 of which were granted on March 8, 2024 and shall vest through March 8, 2027, and 7,256 of which were granted on March 8, 2023 and shall vest through March 8, 2026.

Remarks:

	/s/ Jereme M. Sylvain, as Attorney-in-Fact for Sadie Stern	09/08/2025
	** Signature of Reporting Person	Date
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.

FAQ

What did Sadie Stern report on Form 4 for DXCM?

She reported a sale of 1,466 shares at $80.00 on 09/04/2025, executed under a 10b5-1 plan adopted on 02/20/2025.

How many DexCom shares does Sadie Stern beneficially own after the transaction?

The Form 4 reports beneficial ownership of 105,223 shares following the reported sale.

How many unvested restricted stock units does Ms. Stern have and what are their vesting schedules?

She has 74,450 unvested RSUs: 29,922 (granted 03/08/2025) vest through 03/08/2028; 22,798 (03/08/2025) vest through 03/08/2027; 14,474 (03/08/2024) vest through 03/08/2027; 7,256 (03/08/2023) vest through 03/08/2026.

Was the sale part of a scheduled plan or a one-off transaction?

The sale was executed pursuant to a 10b5-1 trading plan adopted on 02/20/2025, indicating it was part of a pre-established schedule.

Who signed the Form 4 filing for Sadie Stern?

The Form 4 was signed by Jereme M. Sylvain, as Attorney-in-Fact for Sadie Stern on 09/08/2025.