Who owns Winchester Bancorp, Inc./MD/?
Prices and market caps: Cboe delayed data, at least 15 minutes delayed. Not real-time. Fundamentals from company filings.
Institutional ownership of WSBK from SEC Form 13F filings across 21 reporting managers. All positions are from one synchronized reporting period — 2026-06-30 books, filed up to 45 days after quarter end — so every row is comparable.
As of the 2026-06-30 reporting period, 21 institutions disclosed 784,121 shares of Winchester Bancorp, Inc./MD/ worth $10.3M — about 8.7% of shares outstanding; the largest disclosed holder is MANGROVE PARTNERS IM, LLC. Source: SEC Form 13F filings, parsed by EvidInvest.
21
13F holders
$10.3M
value, 2026 filers
8.7%
of shares outstanding (784,121 sh)
5
new positions (2026 filers)
Top institutional holders
ordered by shares owned · positions as of 2026-06-30 · % of fund = share of the manager's own book · % of co. = share of WSBK's shares outstanding
| # | Manager | Shares | Value | % of fund | % of co. | Δ shares QoQ |
|---|---|---|---|---|---|---|
| 1 | MANGROVE PARTNERS IM, LLC | 186,201 | $2.4M | 0.2% | 2.1% | 0.0% |
| 2 | VANGUARD CAPITAL MANAGEMENT LLC | 178,941 | $2.4M | 0.0% | 2% | -1.4% |
| 3 | Integrated Wealth Concepts LLC | 82,000 | $1.1M | 0.0% | 0.9% | +43.9% |
| 4 | Northstar Financial Companies, Inc. | 70,000 | $919,800 | 0.6% | 0.8% | 0.0% |
| 5 | Oppenheimer & Close, LLC | 50,000 | $657,000 | 0.4% | 0.6% | 0.0% |
| 6 | RENAISSANCE TECHNOLOGIES LLC | 31,400 | $412,596 | 0.0% | 0.4% | +1.3% |
| 7 | GEODE CAPITAL MANAGEMENT, LLC | 29,037 | $381,809 | 0.0% | 0.3% | +108.6% |
| 8 | ALLIANCEBERNSTEIN L.P. | 24,656 | $313,131 | 0.0% | 0.3% | 0.0% |
| 9 | VANGUARD FIDUCIARY TRUST CO | 22,708 | $298,383 | 0.0% | 0.3% | +0.6% |
| 10 | RAYMOND JAMES FINANCIAL INC | 20,000 | $262,800 | 0.0% | 0.2% | 0.0% |
| 11 | Steward Partners Investment Advisory, LLC | 19,127 | $251,329 | 0.0% | 0.2% | 0.0% |
| 12 | EagleClaw Capital Managment, LLC | 16,000 | $210,240 | 0.0% | 0.2% | 0.0% |
| 13 | LPL Financial LLC | 15,500 | $203,670 | 0.0% | 0.2% | 0.0% |
| 14 | BlackRock, Inc.NEW | 14,202 | $186,614 | 0.0% | 0.2% | new |
| 15 | RFG - Bristol Wealth Advisors, LLCNEW | 10,158 | $133,476 | 0.0% | 0.1% | new |
| 16 | Sachetta, LLCNEW | 8,000 | $105,120 | 0.1% | 0.1% | new |
| 17 | EASTERN BANK | 4,000 | $52,560 | 0.0% | 0% | +60.0% |
| 18 | ROYAL BANK OF CANADANEW | 2,000 | $26,000 | 0.0% | 0% | new |
| 19 | Tower Research Capital LLC (TRC) | 157 | $2,063 | 0.0% | 0% | -46.6% |
| 20 | UBS Group AG | 18 | $237 | 0.0% | 0% | -86.0% |
| 21 | OSAIC HOLDINGS, INC.NEW | 16 | $210 | 0.0% | 0% | new |
Source: SEC Form 13F-HR filings (institutional managers over $100M in US-listed positions). 13Fs disclose long positions only, up to 45 days after quarter end; each manager's latest filed quarter is shown per row and dollar values are the manager's filed marks. Aggregates labeled "2026 filers" count only managers whose latest book is a 2026 quarter. Related: valuation · options positioning · supply chain. Research, not investment advice.