Winchester BancorpWSBK
13F holders, Q3 2025 (September 30)At the end of Q3 2025, 22 institutions reported holding Winchester Bancorp Inc. (WSBK) in their 13F filings, up 4 from Q2 2025. 4 opened new positions and 0 sold out. The largest holders were Mangrove Partners Im, LLC ($1.8M), M3F, Inc. ($788K) and Northstar Financial Companies, Inc. ($669K). 2 famous investors held it, including Ken Griffin (0.0% of Citadel Advisors's portfolio) and Israel Englander (0.0% of Millennium Management's portfolio).
- Company
- Winchester Bancorp Inc.
- CUSIP
- 97269D103
- Latest filing quarter
- Q2 2026
History
Number of 13F holders
Total Exit/New Position Q2 2025 → Q3 2025
| Institutions | Total Value | |
|---|---|---|
| New Positions | 4 | $731K |
| Exits | 0 | $0 |
All 13F filers, Q2 2025 → Q3 2025: 128,920 shares bought and 40,892 shares sold, net +88,028 shares. Counts holders who added, trimmed, opened or closed a position; split-adjusted.
Ownership 22 holders
| Mangrove Partners Im, LLC | 0.15% | Add +10.6% | 186,949 | $1.8M |
| M3F, Inc. | 0.22% | Add +39.2% | 82,552 | $788K |
| Northstar Financial Companies, Inc. | 0.62% | New | 70,000 | $669K |
| Vanguard Group Inc. | 0.00% | Add +0.3% | 69,167 | $663K |
| Integrated Wealth Concepts LLC | 0.00% | No change | 55,000 | $525K |
| Oppenheimer & Close, LLC | 0.32% | No change | 50,000 | $478K |
| Citadel Advisors | 0.00% | Reduce -37.0% | 26,438 | $254K |
| Stilwell Value LLC | 0.17% | No change | 25,000 | $239K |
| Geode Capital Management, LLC | 0.00% | Add +13.8% | 23,896 | $229K |
| Raymond James Financial Inc. | 0.00% | No change | 20,000 | $191K |
| Millennium Management | 0.00% | Reduce -18.6% | 18,947 | $182K |
| EagleClaw Capital Managment, LLC | 0.02% | No change | 16,000 | $153K |
| LPL Financial LLC | 0.00% | No change | 15,500 | $148K |
| Lynch & Associates | 0.02% | Reduce -27.5% | 13,183 | $126K |
| Steward Partners Investment Advisory, LLC | 0.00% | Add +330.0% | 10,750 | $103K |
| Benin Management CORP | 0.02% | Reduce -4.8% | 10,000 | $96K |
| UBS Group AG | 0.00% | Reduce -40.5% | 7,801 | $75K |
| Morgan Stanley | 0.00% | New | 4,000 | $38K |
| Eastern Bank | 0.00% | New | 2,500 | $24K |
| Tower Research Capital LLC (TRC) | 0.00% | Reduce -44.6% | 355 | $3K |
| Bank of America Corp. | 0.00% | Reduce -97.8% | 225 | $2K |
| Citigroup Inc. | 0.00% | New | 1 | $10 |
"% of holder's portfolio" is WSBK's weight in each manager's 13F, not the share of Winchester Bancorp Inc. the manager owns.