DexCom, Inc.

The full register, from 13F filings

The Register tab above is hand research: a dozen holders, each traced to the filing it came from. This asks the same question of the whole market for the quarter ended 31-mar-2026, where 943 managers reported a position. Broad where the research is deep, and shallow in the ways a 13F always is.

Built from 13F filings, which report US listed, long, US custodied positions only. A register from this source is a floor rather than a level: a holder's true position can be far larger, as BlackRock's ASML stake shows at 1.28m shares in a 13F against 26.3m in its 13G/A. Holdings held through derivatives, outside US custody, or below a manager's reporting obligation do not appear. Where a holder is marked as a family, its total sums several separate filing entities and describes something no single filing describes; the constituent entities and their share counts are listed so the total can be checked. That roll-up can legitimately exceed the family's own Schedule 13G, because a 13G is filed by one legal entity: Vanguard reports Alphabet through ten advisory entities, and The Vanguard Group Inc itself reported zero after its January 2026 disaggregation.

What a reader needs to know to read these numbers

• Split history, confirmed from a filing: DexCom effected a 4-for-1 forward stock split on 10 Jun 2022 (8-K filed 10 Jun 2022, accession 0001193125-22-171920: 'On June 10, 2022, DexCom, Inc. filed its restated certificate of incorporation to effect a four-for-one forward stock split of the Company's common stock and to increase the total number of authorized shares of common stock from 200,000,000 to 800,000,000'). No further split has occurred since: 'stock split' and related terms return zero hits in DexCom's FY2025 10-K (filed 12 Feb 2026) and the Q2 2026 10-Q (filed 30 Jul 2026). Every share count in this file, both shares_outstanding and every register row, is on the post-split (current) basis; none required restatement.
• shares_outstanding (377,360,765) is DexCom's own 10-Q cover-page figure, 'As of July 23, 2026, there were 377,360,765 shares of the registrant's common stock outstanding,' from the Q2 2026 10-Q filed 30 Jul 2026.
• Holdings side is empty. Checked: DexCom's FY2025 10-K (filed 12 Feb 2026, period ended 31 Dec 2025) and Q2 2026 10-Q (filed 30 Jul 2026, period ended 30 Jun 2026), searched for 'equity method', 'equity investment', 'non-marketable', 'strategic investment', 'joint venture', 'unrealized gain', 'cost method', 'unconsolidated', 'minority interest', 'affiliate', 'equity securities of', 'percent interest', 'ownership interest', 'our investment in', and several guessed investee names. DexCom carries a single combined balance of non-marketable equity investments ($209.5 million as of 30 Jun 2026, $218.0 million as of 31 Dec 2025) with no individual investee named anywhere in either filing: this is the combined-balance trap and sizes none of them, so no holdings row is written. Exhibit 21.1 of the FY2025 10-K was also checked for an ownership-percentage column (the 'read Exhibit 21' technique); it is a bare wholly-owned-subsidiary jurisdiction list (Ireland, Malaysia, etc.) with no percentage column and no joint ventures, a genuine negative rather than evidence of looking in the wrong place. The one 'acquisition' event disclosed in the Q2 2026 10-Q ($41.2 million, net of cash acquired) is described as 'accounted for as an acquisition of a group of assets,' i.e. a wholly owned asset purchase, not an equity stake, and is excluded per the brief.
• Self-gate, computed on this final file exactly as the chart computes it: 12 register rows, none marked is_aggregate and none with rolls_up_into (no membership overlap to net out). Raw share sum = 165,890,927. 165,890,927 / 377,360,765 = 43.96% of shares_outstanding. Within the expected 25-45% band.
• BlackRock's fresh Q2 2026 13F-HR figure is materially higher than DexCom's own 15 Apr 2026 DEF 14A figure as of its 1 Apr 2026 record date: 38,244,137 shares (this file, 30 Jun 2026) vs 32,504,140 shares, 8.4% (proxy, 1 Apr 2026). Vanguard is close but also higher: 48,889,884 (this file, 30 Jun 2026) vs 49,455,578 shares, 12.8% (proxy, 1 Apr 2026); the proxy's Vanguard figure is actually slightly larger than the fresh 13F sum, plausibly reflecting entities outside the 8 swept here or timing noise. Per the brief's rule to prefer the fresher Q2 13F over a stale proxy-quoted figure, the 30 Jun 2026 13F figures are used as the register rows; both proxy figures are retained in each row's method_note for reconciliation.
• Implied per-share price from Q2 2026 13F dollar values clusters tightly at $67.35 across Vanguard, BlackRock, State Street, Baillie Gifford, Wellington, Amundi, Capital Group and T. Rowe Price (confirming the T. Rowe values-in-thousands reading); Geode ($67.13), AllianceBernstein ($62.80) and JPMorgan ($69.98) deviate somewhat, ordinary 13F valuation-date noise across large multi-account filers and not treated as an error in the share counts themselves.
• DexCom's market cap ($33.81 billion) and current stock price ($89.60) are from stockanalysis.com as of 18 Aug 2026 (an aggregator, used only for the company.market_cap_usd field, not for any sourced holding or register figure).