Vanguard discloses 19.3M Dexcom shares as 5.02% holding (NASDAQ: DXCM)

Rhea-AI Filing Summary

Dexcom Inc ownership disclosure: Vanguard Portfolio Management reports beneficial ownership of 19,322,566 shares of Common Stock, representing 5.02% of the class as of 03/31/2026. The filing shows sole dispositive power over 19,322,566 shares and sole voting power of 102,613 shares. The disclosure states ownership includes securities held by Vanguard funds and certain affiliates and is signed on 04/29/2026 by Ashley Grim.

Insights

Institutional Ownership Analyst

Vanguard holds a >5% stake in Dexcom, reported as beneficial ownership via managed accounts.

The filing identifies 19,322,566 shares and a 5.02% ownership stake as of 03/31/2026. This is reported under Schedule 13G, which typically describes passive or investment-manager holdings rather than activist intent.

Watch subsequent filings for any change in voting/dispositive power or conversion to Schedule 13D; timing of any trading activity is not included in the excerpt.

Corporate Governance Specialist

Disclosure clarifies power allocation across Vanguard entities and fund sleeves.

The statement explains that Vanguard Portfolio Management LLC exercises dispositive power across funds and affiliated business divisions. The filing lists sole voting power of 102,613 shares and shared powers as zero, indicating voting control is limited relative to dispositive control.

Investors may track whether any affiliate-level reallocations or subsequent amendments alter reported voting authority; those details are not included here.

Key Figures

Beneficial ownership: 19,322,566 shares Percent of class: 5.02% Sole voting power: 102,613 shares +3 more

6 metrics

Beneficial ownership 19,322,566 shares as of 03/31/2026

Percent of class 5.02% Dexcom common stock

Sole voting power 102,613 shares reported voting power

Sole dispositive power 19,322,566 shares reported dispositive/control power

Form type Schedule 13G passive beneficial ownership disclosure

Signature date 04/29/2026 file signed by Ashley Grim

Key Terms

Schedule 13G, Beneficial ownership, Dispositive power, Sole voting power

4 terms

Schedule 13G regulatory

"Name of form: SCHEDULE 13G — passive ownership disclosure"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

Beneficial ownership financial

"Amount beneficially owned: 19322566 — indicates economic ownership"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

Dispositive power regulatory

"Sole power to dispose or to direct the disposition of: 19322566"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

Sole voting power governance

"Sole power to vote or to direct the vote: 102,613"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Dexcom Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

252131107

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 252131107

1

Names of Reporting Persons

Vanguard Portfolio Management

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 102,613.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 19,322,566.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

19,322,566.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.02 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard Portfolio Management LLC and the following affiliates of Vanguard Portfolio Management LLC or business divisions of such affiliates: Vanguard Fiduciary Trust Company and Vanguard Global Advisers, LLC. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Portfolio Management LLC exercises dispositive power, in addition to securities held by clients over which the affiliates or business divisions of such affiliates indicated above exercise dispositive and/or voting power. This Schedule 13G does not include securities, if any, beneficially owned by other subsidiaries or affiliates of Vanguard Portfolio Management LLC, or business divisions of such subsidiaries whose ownership of securities is disaggregated from that of the reporting business unit in accordance with such release.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Dexcom Inc
(b)	Address of issuer's principal executive offices: 6340 Sequence Drive, San Diego, CA, 92121
Item 2.
(a)	Name of person filing: Vanguard Portfolio Management
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd,, Malvern, PA, 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): 252131107
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 19322566
(b)	Percent of class: 5.02 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 102613
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 19322566
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. Vanguard Portfolio Management, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein.No one other person's interest in the securities reported herein is more than 5%.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Vanguard Portfolio Management

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	04/29/2026

FAQ

What stake does Vanguard Portfolio Management report in Dexcom (DXCM)?

Vanguard Portfolio Management reports beneficial ownership of 19,322,566 shares, equal to 5.02% of Dexcom's common stock as of 03/31/2026. The filing attributes dispositive power across Vanguard funds and affiliates.

Does Vanguard have voting control over Dexcom shares?

The filing shows sole voting power for 102,613 shares, while dispositive power applies to 19,322,566 shares. Voting authority is therefore limited relative to overall dispositive control reported.

What filing was used to report this ownership in Dexcom?

The stake is reported on a Schedule 13G, which investment managers use to disclose passive beneficial ownership exceeding 5% without signaling activist intent. The form was signed on 04/29/2026.

Are the Dexcom shares held directly by Vanguard or by affiliated funds?

The disclosure states ownership includes securities held by Vanguard funds and affiliated business divisions, with dispositive power exercised by Vanguard Portfolio Management LLC over those holdings.

Does the filing indicate any change in Vanguard's intentions for the Dexcom stake?

No change of intent is stated. The Schedule 13G format and the text describe holdings as managed across funds and affiliates; the filing does not state plans to acquire additional shares or to take active control.