| 4 | SUSQUEHANNA INTERNATIONAL GROUP, LLP | 133K | $1.1M | -41.3% | 1.376% | 0.00% |
| 5 | Vontobel Holding Ltd. | 123K | $970K | -11.2% | 1.270% | 0.00% |
| 6 | BlackRock, Inc. | 111K | $876K | +8.8% | 1.146% | 0.00% |
| 7 | GEODE CAPITAL MANAGEMENT, LLC | 80K | $631K | +6.9% | 0.826% | 0.00% |
| 8 | CITADEL ADVISORS LLC | 54K | $426K | -9.2% | 0.558% | 0.00% |
| 9 | VANGUARD FIDUCIARY TRUST CO | 49K | $384K | +22.8% | 0.503% | 0.00% |
| 10 | STATE STREET CORP | 34K | $267K | 0.0% | 0.350% | 0.00% |
| 11 | Lion Point Capital, LP | 32K | $249K | 0.0% | 0.326% | 1.19% |
| 12 | CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 31K | $245K | -1.8% | 0.321% | 0.00% |
| 13 | AMERICAN CENTURY COMPANIES INC | 28K | $223K | -54.6% | 0.292% | 0.00% |
| 14 | XTX Topco Ltd | 21K | $164K | — | 0.214% | 0.00% |
| 15 | GOLDMAN SACHS GROUP INC | 15K | $120K | — | 0.157% | 0.00% |
| 16 | NORTHERN TRUST CORP | 15K | $116K | 0.0% | 0.152% | 0.00% |
| 17 | Invesco Ltd. | 13K | $102K | -10.8% | 0.134% | 0.00% |
| 18 | MORGAN STANLEY | 12K | $96K | -44.1% | 0.125% | 0.00% |
| 19 | RAFFA WEALTH MANAGEMENT, LLC | 2 | $49K | — | 0.000% | 0.00% |
| 20 | SIMPLEX TRADING, LLC | 5K | $36K | +49.8% | 0.048% | 0.00% |
| 21 | SBI Securities Co., Ltd. | 4K | $33K | +20.1% | 0.043% | 0.00% |
| 22 | GROUP ONE TRADING LLC | 4K | $29K | +350.7% | 0.038% | 0.00% |
| 23 | JPMORGAN CHASE & CO | 4K | $28K | — | 0.037% | 0.00% |
| 24 | Vanguard Global Advisers, LLC | 2K | $16K | 0.0% | 0.020% | 0.00% |
| 25 | FMR LLC | 2K | $12K | -12.8% | 0.016% | 0.00% |
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 MCRB — a direct measure of their conviction.
| 35.76% |
| 2.83 pp |
| $43M |
| 21% |
| Q4 2024 | 69 | 10% | 38.59% | 161.40 pp | $55M | 82% |
| Q3 2024 | 77 | — | 199.99% | — | $296M | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
6 institutions opened new positions in MCRB during Q2 2026, while 6 fully exited. 5 added to existing positions and 23 trimmed.
MCRB institutional ownership fell by 2.71 percentage points quarter-over-quarter, with a net change of +1 holders.
The top 10 institutions account for 91.8% of all reported 13F value in MCRB, and the top 25 account for 99.9%.
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.
Seres Therapeutics, Inc. (MCRB) Institutional Ownership