Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in BSX held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | BlackRock, Inc. | 131.8M | $8.27B | -3.1% | 8.870% | 0.15% |
| 2 | VANGUARD CAPITAL MANAGEMENT LLC | 96.4M | $6.05B | — | 6.487% | 0.15% |
| 3 | FMR LLC | 74.2M | $4.66B | -23.8% | 4.995% | 0.25% |
| 4 | STATE STREET CORP | 68.0M | $4.27B | +3.3% | 4.575% | 0.15% |
| 5 | GEODE CAPITAL MANAGEMENT, LLC | 33.3M | $2.08B | +2.8% | 2.240% | 0.13% |
| 6 | PRIMECAP MANAGEMENT CO/CA/ | 32.5M | $2.04B | +4.6% | 2.189% | 1.61% |
| 7 | VANGUARD PORTFOLIO MANAGEMENT LLC | 29.8M | $1.87B | — | 2.005% | 0.10% |
| 8 | BANK OF AMERICA CORP /DE/ | 22.8M | $1.43B | -9.4% | 1.531% | 0.10% |
| 9 | MORGAN STANLEY | 22.3M | $1.40B | -3.0% | 1.498% | 0.08% |
| 10 | GOLDMAN SACHS GROUP INC | 19.4M | $1.22B | +15.5% | 1.303% | 0.14% |
| 11 | WELLINGTON MANAGEMENT GROUP LLP | 18.8M | $1.18B | +94.0% | 1.267% | 0.22% |
| 12 | JANUS HENDERSON GROUP PLC | 16.5M | $1.04B | +31.0% | 1.110% | 0.51% |
| 13 | UBS Group AG | 15.8M | $992.2M | +1.4% | 1.064% | 0.15% |
| 14 | Capital World Investors | 15.3M | $960.7M | -43.6% | 1.030% | 0.13% |
| 15 | FRANKLIN RESOURCES INC | 14.7M | $922.9M | +159.1% | 0.990% | 0.23% |
| 16 | DZ BANK AG Deutsche Zentral Genossenschafts Bank, Frankfurt | 14.2M | $888.5M | -23.6% | 0.953% | 0.87% |
| 17 | Amundi | 14.1M | $886.2M | +13.8% | 0.950% | 0.24% |
| 18 | ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | 13.9M | $871.7M | +25.9% | 0.935% | 0.47% |
| 19 | UBS ASSET MANAGEMENT AMERICAS INC | 13.5M | $848.0M | +23.6% | 0.909% | 0.18% |
| 20 | NORTHERN TRUST CORP | 13.4M | $839.2M | -4.0% | 0.900% | 0.11% |
| 21 | Nuveen, LLC | 11.7M | $736.3M | +25.2% | 0.790% | 0.20% |
| 22 | MASSACHUSETTS FINANCIAL SERVICES CO /MA/ | 11.0M | $716.9M | +21.0% | 0.740% | 0.24% |
| 23 | Legal & General Group Plc | 10.6M | $665.2M | -2.5% | 0.713% | 0.15% |
| 24 | Assenagon Asset Management S.A. | 10.1M | $631.1M | +133.6% | 0.677% | 1.01% |
| 25 | Bank of New York Mellon Corp | 9.5M | $598.9M | -15.0% | 0.642% | 0.11% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in BSX — a direct measure of their conviction.
Filings activity in BSX during Q1 2026, grouped by how each filer changed its position.
8 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 1,623 | 6.5% | 112.12% | 63.44 pp | $78.17B | 36% |
| Q4 2025 | 1,736 | +4.7% | 175.56% | 3.39 pp | $122.39B | 1.9% |
| Q3 2025 | 1,658 | +0.3% | 178.95% | 16.30 pp | $124.76B | 8.3% |
| Q2 2025 | 1,653 | +3.8% | 195.25% | +15.04 pp | $136.12B | +8.3% |
| Q1 2025 | 1,593 | +9.9% | 180.21% | +17.81 pp | $125.64B | +11% |
| Q4 2024 | 1,450 | +8.0% | 162.40% | +17.53 pp | $113.22B | +12% |
| Q3 2024 | 1,343 | +5.9% | 144.87% | 12.48 pp | $101.00B | 7.9% |
| Q2 2024 | 1,268 | — | 157.35% | — | $109.70B | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Latest Form 4 transactions by company officers and directors. Insider buys are widely viewed as the highest-conviction signal because executives are risking personal capital.
| Date | Insider | Action | Shares | Price | Value |
|---|---|---|---|---|---|
| May 20, 2026 | Pegus Cheryl | Buy | 2K | $56.49 | $100K |
| May 20, 2026 | LUDWIG EDWARD J | Buy | 4K | $56.68 | $203K |
| May 19, 2026 | Habiger David C | Buy | 2K | $56.95 | $125K |
Quick answers to the most common questions about buying BSX stock.
Based on Q1 2026 13F filings, institutional ownership of Boston Scientific Corporation stands at 112.1%, held across 1,623 reporting institutions.
BlackRock, Inc. is the largest reported institutional holder of BSX, with approximately 131,822,037 shares worth $8.27B as of Q1 2026.
No marquee "smart money" managers (Berkshire, Burry, ARK, Tiger Global, Pershing Square, Baupost, etc.) currently appear among the top 25 institutional holders of BSX.
Our composite Smart Money Score for BSX is 12 out of 100 (Heavy Distribution). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
212 institutions opened new positions in BSX during Q1 2026, while 325 fully exited. 210 added to existing positions and 1,197 trimmed.
BSX institutional ownership fell by 63.44 percentage points quarter-over-quarter, with a net change of -113 holders.
The top 10 institutions account for 42.6% of all reported 13F value in BSX, and the top 25 account for 58.9%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Boston Scientific Corporation (BSX) Institutional Ownership