Winchester Bancorp, Inc.
WSBK- Exchange
- Nasdaq
- Industry
- Savings Institutions, Not Federally Chartered
- SEC CIK
- 0002047235
No open-market purchases or sales by Winchester Bancorp, Inc. insiders were filed in the last 90 days; 21 institutions reported holding it in 13F filings for Q2 2026, worth $9.96M in total; no superinvestor holds it.
13F holders, Q4 2025
Institutional positions in Winchester Bancorp, Inc. as of Dec 31, 2025. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works
- Institutional holders
- 21
- −1 vs. Q3 2025
- Shares held
- 771.3K
- +63.0K (+8.9%) vs. Q3 2025
- Total value
- $8.06M
- +$1.29M (+19.1%) vs. Q3 2025
- New holders
- 2
- 6 more added
- Sold out
- 3
- 5 more reduced
Compare with Q3 2025: new holders, sold out and not filed yet
Holders and value by quarter
Institutions reporting WSBK on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.
| Quarter | Holders | Value |
|---|---|---|
| Q2 2026 | 21 | $9.96M |
| Q1 2026 | 19 | $9.48M |
| Q4 2025 | 21 | $8.06M |
| Q3 2025 | 22 | $6.77M |
| Q2 2025 | 18 | $5.55M |
| Q1 2025 | 0 | $0 |
| Q4 2024 | 0 | $0 |
| Q3 2024 | 0 | $0 |
| Q2 2024 | 0 | $0 |
| Q1 2024 | 0 | $0 |
| Q4 2023 | 0 | $0 |
| Q3 2023 | 0 | $0 |
| Q2 2023 | 0 | $0 |
| Q1 2023 | 0 | $0 |
| Q4 2022 | 0 | $0 |
| Q3 2022 | 0 | $0 |
| Q2 2022 | 0 | $0 |
| Q1 2022 | 0 | $0 |
| Q4 2021 | 0 | $0 |
| Q3 2021 | 0 | $0 |
| Q2 2021 | 0 | $0 |
| Q1 2021 | 0 | $0 |
Institutions, Q4 2025
Shares, value and share of portfolio for each institution holding Winchester Bancorp, Inc.; share changes are against Q3 2025.
| Institution | Shares | Value | % of portfolio | Change in shares | Action |
|---|---|---|---|---|---|
| Mangrove Partners | 186,201 | $1.95M | 0.16% | −748−0.4% | Reduced |
| M3F, Inc. | 143,986 | $1.50M | 0.41% | +61,434+74.4% | Added |
| Vanguard Group Inc | 71,736 | $749.6K | 0.00% | +2,569+3.7% | Added |
| Northstar Financial Companies, Inc. | 70,000 | $731.5K | 0.58% | 00.0% | Unchanged |
| Integrated Wealth Concepts LLC | 57,000 | $595.6K | 0.01% | +2,000+3.6% | Added |
| Oppenheimer & Close, LLC | 50,000 | $522.5K | 0.36% | 00.0% | Unchanged |
| Renaissance Technologies LLC | 26,502 | $276.9K | 0.00% | +26,502 | New |
| Geode Capital Management, LLC | 26,502 | $276.9K | 0.00% | +2,606+10.9% | Added |
| Alliancebernstein L.P. | 24,656 | $257.7K | 0.00% | +24,656 | New |
| Citadel Advisors LLC | 20,999 | $219.4K | 0.00% | −5,439−20.6% | Reduced |
| Raymond James Financial Inc | 20,000 | $209.0K | 0.00% | 00.0% | Unchanged |
| Steward Partners Investment Advisory, LLC | 19,127 | $199.9K | 0.00% | +8,377+77.9% | Added |
| Millennium Management LLC | 16,082 | $168.1K | 0.00% | −2,865−15.1% | Reduced |
| EagleClaw Capital Managment, LLC | 16,000 | $167.2K | 0.02% | 00.0% | Unchanged |
| LPL Financial LLC | 15,500 | $162.0K | 0.00% | 00.0% | Unchanged |
| Morgan Stanley | 4,000 | $41.8K | 0.00% | 00.0% | Unchanged |
| Eastern Bank | 2,500 | $26.1K | 0.00% | 00.0% | Unchanged |
| Tower Research Capital LLC (TRC) | 255 | $2.67K | 0.00% | −100−28.2% | Reduced |
| Bank of America Corp | 227 | $2.37K | 0.00% | +2+0.9% | Added |
| UBS Group AG | 3 | $31 | 0.00% | −7,798−100.0% | Reduced |
| Citigroup Inc | 1 | $10 | 0.00% | 00.0% | Unchanged |
| Stilwell Value LLC | 0 | $0 | 0.00% | −25,000−100.0% | Sold out |
| Lynch & Associates | 0 | $0 | 0.00% | −13,183−100.0% | Sold out |
| Benin Management CORP | 0 | $0 | 0.00% | −10,000−100.0% | Sold out |