Winchester Bancorp, Inc.
Ownership
Ownership Structure
Who owns Winchester Bancorp, Inc. (WSBK)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 42.2% of the shares are freely tradable; institutional investors hold 8.4%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Mangrove Partners | 2.08 | 186,201 | +0.0 | 03/31/2026 |
| Vanguard Capital Management, LLC | 2.03 | 181,513 | +0.0 | 03/31/2026 |
| Integrated Wealth Concepts LLC | 0.92 | 82,000 | +43.9 | 06/30/2026 |
| Northstar Financial Companies, INC. | 0.78 | 70,000 | +0.0 | 06/30/2026 |
| Oppenheimer & Close Inc | 0.56 | 50,000 | +0.0 | 06/30/2026 |
| Renaissance Technologies Corp | 0.35 | 31,000 | +17.0 | 03/31/2026 |
| AllianceBernstein L.P. | 0.28 | 24,656 | +0.0 | 03/31/2026 |
| M3F, Inc. | 0.27 | 24,586 | -82.9 | 03/31/2026 |
| Vanguard Fiduciary Trust Co | 0.25 | 22,562 | +0.0 | 03/31/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Vanguard MStar Total Stk Mkt Idx Invest | 1.47 | 132,140 | +0.0 | 08/31/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Data as of: September 25, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.