Boston Scientific Corporation

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 1,643 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

• Acquired-subsidiary exclusions. Several of the medtech names the brief flags as characteristic Boston Scientific investees are, as of the Q2 2026 10-Q, wholly owned operating subsidiaries and are excluded from holdings: Bolt Medical, Inc. (BSX held ~26% since 2019, acquired the remainder 1 Apr 2025), SoniVie Ltd. (acquired outright 7 May 2025), Axonics, Inc. (acquired outright 15 Nov 2024), Nalu Medical, Inc. (BSX held ~9% since 2017, acquired the remainder 27 Jan 2026), and Silk Road Medical (named in the FY2025 10-K as a completed acquisition, integrated into Cardiovascular). None appears in holdings.
• Acotec Scientific Holdings Limited is also excluded. Boston Scientific acquired a majority stake in Acotec in Q1 2023 and consolidates Acotec's financial statements on a one-quarter lag as a controlled, less-than-wholly-owned subsidiary (the FY2025 10-K notes ~$57 million of unrestricted cash held by Acotec specifically). Because BSX has a controlling financial interest and consolidates it, Acotec is treated like the brief's wholly-owned-subsidiary exclusion rather than as a minority holding, even though a minority public float remains outside BSX's control.
• The TAVR Option (the right to acquire MiRus's TAVR business for up to $3.0 billion of additional payments) is excluded from holdings as an acquisition option / derivative-like instrument per the brief's rule to exclude derivatives; its notional is noted here rather than sized as a position.
• Boston Scientific's Q2 2026 10-Q reports only two combined balance-sheet lines for its non-Penumbra strategic and equity-method investments: 'Equity method investments' of $1,308 million (30 Jun 2026) vs $396 million (31 Dec 2025), and 'Measurement alternative investments' (privately-held equity securities without readily determinable fair value, plus publicly-held equity securities, convertible notes and fair-value securities) of $938 million vs $286 million. Both totals cover multiple, mostly unnamed investees; per the brief's rule against assigning a combined balance to one investee, no dollar value is attached to MiRus or Scivita individually, and no other named investee within these balances was identified in the filing.
• Register reconciliation on the three largest holders. Boston Scientific's 2026 proxy, based on 13G/A filings (Vanguard amendment filed 13 Feb 2024, reflecting a position as of 29 Dec 2023; BlackRock and FMR/Abigail Johnson similarly dated), reports The Vanguard Group at 125,449,595 shares (8.44%), BlackRock, Inc. at 113,006,671 shares (7.60%), and FMR LLC/Abigail P. Johnson at 110,320,938 shares (7.42%), against 1,486,175,167 shares outstanding as of 6 March 2026. The register instead uses each manager's Q2 2026 Form 13F-HR (30 June 2026 position dates): Vanguard's successor entities sum to 126,880,347 shares, BlackRock to 129,680,916 shares (meaningfully higher than the stale 13G figure), and FMR to 45,702,845 shares (meaningfully lower than the stale 13G figure, consistent with Fidelity actively trimming the position between early 2024 and mid-2026 rather than a data error).
• Vanguard Group Inc (CIK 0000102909) filed 13F-NT (notice, no holdings) for the quarter ended 30 June 2026. Per the brief's Vanguard rule, this is the 13F-NT case: successor filers Vanguard Capital Management LLC and Vanguard Portfolio Management LLC ARE the position and are summed into one substituted 'The Vanguard Group' row rather than listed separately or alongside a parent row.
• Capital Group is explicitly NOT the Vanguard case: it is three separately registered, separately filing 13F managers of one family (Capital World Investors, Capital International Investors, Capital Research Global Investors). Two of the three (Capital World Investors CIK 0001422849 and Capital Research Global Investors CIK 0001422848) hold BSX for Q2 2026 and are summed into one 'Capital Group' row; the third (Capital International Investors, CIK 0001562230) filed a 13F-HR for the same quarter but has no BSX position in its information table.
• Percentages are computed against 1,449,229,526 common shares outstanding as of 30 July 2026 (Q2 2026 10-Q cover page), except the two proxy-sourced insider rows, which use the proxy's own denominator of 1,486,175,167 shares as of 6 March 2026.
• Market capitalisation ($74.93 billion) and the $51.70 share price are stockanalysis.com's figures as of 17 August 2026, intraday. Cross-check: 1,449,229,526 shares x $51.70 implies approximately $74.93 billion, consistent with the reported market cap.
• Self-gate check: summing the 13 non-aggregate, non-insider register rows (Vanguard, BlackRock, State Street, FMR, Norges Bank, Geode, Capital Group, JPMorgan, Morgan Stanley, Wellington, Franklin, Bank of America, Wells Fargo) gives 545,986,795 shares against 1,449,229,526 shares outstanding, or 37.67%, within the expected 15 to 55 percent range.