WSBK
Winchester Bancorp, Inc./MD/Company with tickers: WSBK
CIK
2047235
CUSIP
97269D103
Shares Outstanding
8,960,743
13F Activity (30d)
13 filings
11 filers
Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.
Holders: 19
Total Value: $9,531,739
Total Shares: 750,531
Institutional Ownership Trend
5 quarters
Holder Concentration
Across 19 13F filers · Δ vs Dec 31, 2025Top Holder
24.8%
+0.7 pts
Top 5
72.6%
+4.0 pts
Top 10
88.9%
+1.1 pts
HHI
1,466
Broadly held+202
Quarterly Activity
vs Dec 31, 2025
New
2
Increased
3
Decreased
3
Sold Out
4
Unchanged
11
Holder count:
-2
Institutional value:
+18.3%
Shares held:
-2.7%
Top Buyers
vs Dec 31, 2025| Institution | Added | Now Holds | Open |
|---|---|---|---|
| Large RENAISSANCE TECHNOLOGIES LLC | +4,498 | 31,000 | |
| Mega UBS Group AG | +126 | 129 | |
| Mid Tower Research Capital LLC (TRC) | +39 | 294 |
Top Sellers
vs Dec 31, 2025| Institution | Sold | Now Holds | Open |
|---|---|---|---|
| Small M3F, Inc. | −119,400 | 24,586 | |
| Mega GEODE CAPITAL MANAGEMENT, LLC | −12,582 | 13,920 | |
| Mega MILLENNIUM MANAGEMENT LLC | −4,539 | 11,543 |
Top New Positions
vs Dec 31, 2025| Institution | Acquired | Value (USD) | Open |
|---|---|---|---|
| Mega VANGUARD CAPITAL MANAGEMENT LLC | 181,513 | $2,305,215 | |
| Mega VANGUARD FIDUCIARY TRUST CO | 22,562 | $286,537 |
Top Sold-Out Positions
vs Dec 31, 2025| Institution | Previously Held | Last Value (USD) | Open |
|---|---|---|---|
| Mega VANGUARD GROUP INC | 71,736 | $749,640 | |
| Mega CITADEL ADVISORS LLC | 20,999 | $219,439 | |
| Mega BANK OF AMERICA CORP /DE/ | 227 | $2,371 | |
| Mega CITIGROUP INC | 1 | $10 |
| Holder | Value (USD) | % of 13F | Shares | Type | Discretion | Filed | Open | |||
|---|---|---|---|---|---|---|---|---|---|---|
| Mid MANGROVE PARTNERS IM, LLC | $2,364,752 | 24.81% | 186,201 | Shares | Sole | 2026-05-15 | ||||
| Mega VANGUARD CAPITAL MANAGEMENT LLC | $2,305,215 | 24.18% | 181,513 | Shares | Defined | 2026-05-15 | ||||
| Micro Northstar Financial Companies, Inc. | $889,000 | 9.33% | 70,000 | Shares | Sole | 2026-05-05 | ||||
| Mid Integrated Wealth Concepts LLC | $723,900 | 7.59% | 57,000 | Shares | Sole | 2026-05-15 | ||||
| Small Oppenheimer & Close, LLC | $635,000 | 6.66% | 50,000 | Shares | Sole | 2026-05-12 | ||||
| Large RENAISSANCE TECHNOLOGIES LLC | $393,700 | 4.13% | 31,000 | Shares | Sole | 2026-05-14 | ||||
| Mega ALLIANCEBERNSTEIN L.P. | $313,131 | 3.29% | 24,656 | Shares | Defined | 2026-05-15 | ||||
| Small M3F, Inc. | $312,242 | 3.28% | 24,586 | Shares | Sole | 2026-04-28 | ||||
| Mega VANGUARD FIDUCIARY TRUST CO Bank | $286,537 | 3.01% | 22,562 | Shares | Defined | 2026-05-08 | ||||
| Mega RAYMOND JAMES FINANCIAL INC | $254,000 | 2.66% | 20,000 | Shares | Defined | 2026-05-14 | ||||
| Large Steward Partners Investment Advisory, LLC | $242,912 | 2.55% | 19,127 | Shares | Sole | 2026-05-08 | ||||
| Small EagleClaw Capital Managment, LLC | $203,200 | 2.13% | 16,000 | Shares | Sole | 2026-05-08 | ||||
| Mega LPL Financial LLC | $196,850 | 2.07% | 15,500 | Shares | Sole | 2026-05-06 | ||||
| Mega GEODE CAPITAL MANAGEMENT, LLC | $176,783 | 1.85% | 13,920 | Shares | Defined | 2026-05-15 | ||||
| Mega MILLENNIUM MANAGEMENT LLC | $146,596 | 1.54% | 11,543 | Shares | Sole | 2026-05-15 | ||||
| Mega MORGAN STANLEY | $50,800 | 0.53% | 4,000 | Shares | Defined | 2026-05-15 | ||||
| Mid EASTERN BANK Bank | $31,750 | 0.33% | 2,500 | Shares | Sole | 2026-04-07 | ||||
| Mid Tower Research Capital LLC (TRC) | $3,733 | 0.04% | 294 | Shares | Defined | 2026-05-15 | ||||
| Mega UBS Group AG | $1,638 | 0.02% | 129 | Shares | Defined | 2026-05-05 | ||||
| No holders match your search. | ||||||||||