Who owns BSX (BSX)
Which tracked institutional funds hold BSX, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See BSX company fundamentals →
Ownership as of the 2026-Q1 13F filings. 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
The tracked-fund tape on BSX is one-sided between 2025-Q4 and 2026-Q1: 241 added or opened and 932 trimmed or exited — on balance reducing.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
BSX’s largest tracked holder by dollar value, VANGUARD GROUP INC, sizes it at 0.2% of its own reported 13F book, while the median holder sizes it at 0.2% of theirs — a 0.0pp gap the other way — the median holder sizes BSX more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in BSX divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 1656 tracked filers holding BSX, 857 increased or opened the position and 946 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in BSX between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 104
- VANGUARD CAPITAL MANAGEMENT LLC$6.0B
- VANGUARD PORTFOLIO MANAGEMENT LLC$1.9B
- VANGUARD FIDUCIARY TRUST CO$526M
- Vanguard Global Advisers, LLC$204M
- VANGUARD ASSET MANAGEMENT, Ltd$161M
- SEB Asset Management AB$130M
Full exits 118
- VANGUARD GROUP INC$13.3B
- TWO SIGMA ADVISERS, LP$601M
- Egerton Capital (UK) LLP$513M
- SurgoCap Partners LP$244M
- VIKING GLOBAL INVESTORS LP$239M
- AXIOM INVESTORS LLC /DE$157M
Largest adds
- D. E. Shaw & Co., Inc.$453M
- FRANKLIN RESOURCES INC$369M
- TWO SIGMA INVESTMENTS, LP$355M
- WELLINGTON MANAGEMENT GROUP LLP$254M
- 1832 Asset Management L.P.$245M
- AQR CAPITAL MANAGEMENT LLC$222M
Largest trims
- BlackRock, Inc.$5.0B
- FMR LLC$4.6B
- STATE STREET CORP$2.0B
- Capital World Investors$1.6B
- GEODE CAPITAL MANAGEMENT, LLC$994M
- BANK OF AMERICA CORP /DE/$967M
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. trimmed | 127,655,311 | $8.0B | 9.2% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 96,411,568 | $6.0B | 7.0% | 2026-Q1 |
| FMR LLC trimmed | 74,190,749 | $4.7B | 5.4% | 2026-Q1 |
| STATE STREET CORP added | 67,986,847 | $4.3B | 4.9% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 33,350,157 | $2.1B | 2.4% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 33,285,757 | $2.1B | 2.4% | 2026-Q1 |
| PRIMECAP MANAGEMENT CO/CA/ added | 32,529,774 | $2.0B | 2.3% | 2026-Q1 |
| NORGES BANK trimmed | 19,969,664 | $2.0B | 2.3% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 29,796,211 | $1.9B | 2.2% | 2026-Q1 |
| D. E. Shaw & Co., Inc. added | 24,312,352 | $1.5B | 1.8% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ trimmed | 22,756,646 | $1.4B | 1.6% | 2026-Q1 |
| MORGAN STANLEY trimmed | 22,266,664 | $1.4B | 1.6% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 18,891,624 | $1.2B | 1.4% | 2026-Q1 |
| WELLINGTON MANAGEMENT GROUP LLP added | 18,797,489 | $1.2B | 1.4% | 2026-Q1 |
| Bollard Group LLC trimmed | 18,532,173 | $1.2B | 1.3% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC added | 16,497,366 | $1.0B | 1.2% | 2026-Q1 |
| Capital World Investors trimmed | 15,309,738 | $961M | 1.1% | 2026-Q1 |
| UBS Group AG trimmed | 14,824,662 | $930M | 1.1% | 2026-Q1 |
| FRANKLIN RESOURCES INC added | 14,498,741 | $910M | 1.0% | 2026-Q1 |
| Amundi added | 14,122,913 | $886M | 1.0% | 2026-Q1 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added | 13,891,668 | $872M | 1.0% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 13,513,771 | $848M | 1.0% | 2026-Q1 |
| NORTHERN TRUST CORP trimmed | 13,373,881 | $839M | 1.0% | 2026-Q1 |
| DZ BANK AG Deutsche Zentral Genossenschafts Bank, Frankfurt am Main trimmed | 13,229,644 | $830M | 1.0% | 2026-Q1 |
| Nuveen, LLC added | 11,734,314 | $736M | 0.8% | 2026-Q1 |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ added | 10,996,572 | $717M | 0.8% | 2026-Q1 |
| Legal & General Group Plc trimmed | 10,600,766 | $665M | 0.8% | 2026-Q1 |
| Assenagon Asset Management S.A. added | 10,057,936 | $631M | 0.7% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 9,543,875 | $599M | 0.7% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 9,411,231 | $591M | 0.7% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 9,170,180 | $575M | 0.7% | 2026-Q1 |
| Invesco Ltd. trimmed | 8,895,894 | $558M | 0.6% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 8,382,185 | $526M | 0.6% | 2026-Q1 |
| CANADA PENSION PLAN INVESTMENT BOARD added | 8,035,947 | $504M | 0.6% | 2026-Q1 |
| PARNASSUS INVESTMENTS, LLC added | 8,003,820 | $502M | 0.6% | 2026-Q1 |
| Vontobel Holding Ltd. added | 7,978,214 | $501M | 0.6% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 7,873,368 | $494M | 0.6% | 2026-Q1 |
| EDGEWOOD MANAGEMENT LLC trimmed | 7,629,399 | $479M | 0.6% | 2026-Q1 |
| FARALLON CAPITAL MANAGEMENT LLC added | 7,470,684 | $469M | 0.5% | 2026-Q1 |
| Ninety One UK Ltd added | 7,308,540 | $459M | 0.5% | 2026-Q1 |
| 1832 Asset Management L.P. added | 7,252,746 | $455M | 0.5% | 2026-Q1 |
| SCHRODER INVESTMENT MANAGEMENT GROUP trimmed | 7,252,007 | $455M | 0.5% | 2026-Q1 |
| Capital Research Global Investors trimmed | 7,080,887 | $444M | 0.5% | 2026-Q1 |
| NEUBERGER BERMAN GROUP LLC added | 7,072,894 | $444M | 0.5% | 2026-Q1 |
| BNP PARIBAS ASSET MANAGEMENT Holding S.A. trimmed | 6,966,229 | $437M | 0.5% | 2026-Q1 |
| DEUTSCHE BANK AG\ trimmed | 6,653,275 | $417M | 0.5% | 2026-Q1 |
| ROYAL BANK OF CANADA added | 6,273,263 | $394M | 0.5% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 6,097,777 | $383M | 0.4% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 5,569,880 | $350M | 0.4% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC trimmed | 5,573,439 | $349M | 0.4% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 5,237,467 | $327M | 0.4% | 2026-Q1 |
| Pictet Asset Management Holding SA added | 5,120,057 | $321M | 0.4% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 5,101,806 | $320M | 0.4% | 2026-Q1 |
| BARCLAYS PLC added | 5,024,157 | $315M | 0.4% | 2026-Q1 |
| FIRST MANHATTAN CO. LLC. added | 4,911,217 | $308M | 0.4% | 2026-Q1 |
| LAZARD ASSET MANAGEMENT LLC added | 4,880,504 | $306M | 0.4% | 2026-Q1 |
| ADAGE CAPITAL PARTNERS GP, L.L.C. added | 4,633,237 | $291M | 0.3% | 2026-Q1 |
| Ensign Peak Advisors, Inc added | 4,507,242 | $283M | 0.3% | 2026-Q1 |
| Swiss National Bank added | 4,350,600 | $273M | 0.3% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 4,217,314 | $265M | 0.3% | 2026-Q1 |
| MAVERICK CAPITAL LTD added | 4,195,089 | $263M | 0.3% | 2026-Q1 |
| JANE STREET GROUP, LLC added | 4,032,117 | $253M | 0.3% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC trimmed | 4,337,804 | $241M | 0.3% | 2026-Q1 |
| Man Group plc trimmed | 3,718,731 | $233M | 0.3% | 2026-Q1 |
| National Pension Service trimmed | 3,698,745 | $232M | 0.3% | 2026-Q1 |
| Point72 Asset Management, L.P. added | 3,687,315 | $231M | 0.3% | 2026-Q1 |
| MARSHALL WACE, LLP added | 3,611,020 | $227M | 0.3% | 2026-Q1 |
| Holocene Advisors, LP trimmed | 3,428,736 | $215M | 0.2% | 2026-Q1 |
| Sumitomo Mitsui Trust Group, Inc. trimmed | 3,422,813 | $215M | 0.2% | 2026-Q1 |
| HSBC HOLDINGS PLC trimmed | 3,399,703 | $213M | 0.2% | 2026-Q1 |
| Mitsubishi UFJ Asset Management Co., Ltd. added | 3,364,108 | $211M | 0.2% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 3,244,238 | $204M | 0.2% | 2026-Q1 |
| FIL Ltd trimmed | 3,214,116 | $202M | 0.2% | 2026-Q1 |
| Rathbones Group PLC added | 3,179,435 | $200M | 0.2% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 3,152,005 | $198M | 0.2% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC trimmed | 3,029,097 | $190M | 0.2% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN trimmed | 2,971,322 | $186M | 0.2% | 2026-Q1 |
| Alecta Tjanstepension Omsesidigt added | 2,865,900 | $180M | 0.2% | 2026-Q1 |
| Unisphere Establishment added | 2,802,700 | $176M | 0.2% | 2026-Q1 |
| Aberdeen Group plc added | 2,766,280 | $174M | 0.2% | 2026-Q1 |
| RHUMBLINE ADVISERS trimmed | 2,674,641 | $168M | 0.2% | 2026-Q1 |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE added | 2,629,613 | $165M | 0.2% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC trimmed | 2,617,803 | $164M | 0.2% | 2026-Q1 |
| Handelsbanken Fonder AB added | 2,587,061 | $162M | 0.2% | 2026-Q1 |
| VANGUARD ASSET MANAGEMENT, Ltd new | 2,567,095 | $161M | 0.2% | 2026-Q1 |
| Mariner, LLC added | 2,484,960 | $156M | 0.2% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. trimmed | 1,625,785 | $155M | 0.2% | 2026-Q1 |
| KBC Group NV trimmed | 2,420,506 | $152M | 0.2% | 2026-Q1 |
| Temasek Holdings (Private) Ltd added | 2,399,426 | $151M | 0.2% | 2026-Q1 |
| Allianz Asset Management GmbH added | 2,393,824 | $150M | 0.2% | 2026-Q1 |
| ORBIMED ADVISORS LLC trimmed | 2,382,100 | $149M | 0.2% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 2,318,420 | $146M | 0.2% | 2026-Q1 |
| VANGUARD GROUP INC added | 139,685,720 | $13.3B | 15.3% | 2025-Q4 stale |
| TWO SIGMA ADVISERS, LP added | 6,298,460 | $601M | 0.7% | 2025-Q4 stale |
| Egerton Capital (UK) LLP added | 5,385,084 | $513M | 0.6% | 2025-Q4 stale |
| AXA Investment Managers S.A. new | 2,816,813 | $275M | 0.3% | 2025-Q3 stale |
| SurgoCap Partners LP trimmed | 2,559,210 | $244M | 0.3% | 2025-Q4 stale |
| VIKING GLOBAL INVESTORS LP trimmed | 2,509,808 | $239M | 0.3% | 2025-Q4 stale |
| JARISLOWSKY, FRASER Ltd trimmed | 2,192,794 | $214M | 0.2% | 2025-Q3 stale |
| AXIOM INVESTORS LLC /DE trimmed | 1,641,563 | $157M | 0.2% | 2025-Q4 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.