Winchester Bancorp, Inc. Common Stock (WSBK) Holders & Ownership

Winchester Bancorp, Inc. Common Stock (WSBK) ownership: Winchester Bancorp, MHC. 59% · institutions 7% · index and ETF funds 1% (13F 2026-03-31). Insider activity, 90 days: 0 sales, 0 open-market buys. SEC EDGAR first-party data.

Top Institutional Holders (13F, rolled up by parent)

Source: SEC Form 13F
HolderSharesMarket Value% OutstandingReported
Vanguard204075.00$2.59M2.2%2026-03-31
Mangrove Partners Im, LLC186201.00$2.36M2.0%2026-03-31
Northstar Financial Companies, Inc.70000.00$889000.000.8%2026-03-31
Integrated Wealth Concepts LLC57000.00$723900.000.6%2026-03-31
Oppenheimer50000.00$635000.000.5%2026-03-31
Renaissance Technologies31000.00$393700.000.3%2026-03-31
M3F, Inc.24586.00$312000.000.3%2026-03-31
AllianceBernstein24656.00$257655.000.3%2026-03-31

Insider Trading Activity (Form 4)

Source: SEC Form 4
InsiderTransactionValueDate
Sellnull2026-05-26
Sellnull2026-05-21
Sellnull2026-05-07
Sellnull2026-05-07
Sellnull2026-05-05
Sellnull2026-05-05
Sellnull2026-05-05
Sellnull2026-05-01

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Institutional data from SEC Form 13F. Insider data from SEC Form 4. Congressional data from STOCK Act disclosures. Not personalized investment advice.