Winchester BancorpWSBK
13F holders, Q4 2025 (December 31)At the end of Q4 2025, 21 institutions reported holding Winchester Bancorp Inc. (WSBK) in their 13F filings, down 1 from Q3 2025. 2 opened new positions and 3 sold out. The largest holders were Mangrove Partners Im, LLC ($1.9M), M3F, Inc. ($1.5M) and Vanguard Group Inc. ($750K). 3 famous investors held it, including Jim Simons / Peter Brown (0.0% of Renaissance Technologies's portfolio), 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 Q3 2025 → Q4 2025
| Institutions | Total Value | |
|---|---|---|
| New Positions | 2 | $535K |
| Exits | 3 | $460K |
All 13F filers, Q3 2025 → Q4 2025: 128,146 shares bought and 65,133 shares sold, net +63,013 shares. Counts holders who added, trimmed, opened or closed a position; split-adjusted.
Ownership 21 holders
| Mangrove Partners Im, LLC | 0.16% | Reduce -0.4% | 186,201 | $1.9M |
| M3F, Inc. | 0.41% | Add +74.4% | 143,986 | $1.5M |
| Vanguard Group Inc. | 0.00% | Add +3.7% | 71,736 | $750K |
| Northstar Financial Companies, Inc. | 0.58% | No change | 70,000 | $732K |
| Integrated Wealth Concepts LLC | 0.01% | Add +3.6% | 57,000 | $596K |
| Oppenheimer & Close, LLC | 0.36% | No change | 50,000 | $523K |
| Renaissance Technologies | 0.00% | New | 26,502 | $277K |
| Geode Capital Management, LLC | 0.00% | Add +10.9% | 26,502 | $277K |
| Alliancebernstein L.P. | 0.00% | New | 24,656 | $258K |
| Citadel Advisors | 0.00% | Reduce -20.6% | 20,999 | $219K |
| Raymond James Financial Inc. | 0.00% | No change | 20,000 | $209K |
| Steward Partners Investment Advisory, LLC | 0.00% | Add +77.9% | 19,127 | $200K |
| Millennium Management | 0.00% | Reduce -15.1% | 16,082 | $168K |
| EagleClaw Capital Managment, LLC | 0.02% | No change | 16,000 | $167K |
| LPL Financial LLC | 0.00% | No change | 15,500 | $162K |
| Morgan Stanley | 0.00% | No change | 4,000 | $42K |
| Eastern Bank | 0.00% | No change | 2,500 | $26K |
| Tower Research Capital LLC (TRC) | 0.00% | Reduce -28.2% | 255 | $3K |
| Bank of America Corp. | 0.00% | Add +0.9% | 227 | $2K |
| UBS Group AG | 0.00% | Reduce -100.0% | 3 | $31 |
| Citigroup Inc. | 0.00% | No change | 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.