$WSBK

$13.40 +$0.31 (2.37%) Close

$WSBK Overview Financial Statements SEC Filings Executives News Red Flags Capital Raising Ownership Insider Transactions Congressional Trades

Ownership

13F as of Q2 2026 · 9.3M shares outstanding

Who owns WSBK?

By type of holder

Institutions 8.2% Insiders 59.3% Everyone else 32.5%

Concentration Top 10 holders own 63.2%

Winchester Bancorp, MHC 55.0% · Mangrove Partners Im, LLC 2.0%

Institutional ownership

8.2%

+0.1 pts vs last qtr

Institutional holders

+2 vs last qtr

Net shares bought

+8.6K

by institutions in Q2 2026

New / sold out

5 / 3

positions opened vs closed

How is ownership changing?

Institutions, last 8 quarters

Biggest buyers in Q2 2026

Geode Capital Management, LLC +15.1K
BlackRock, Inc. NEW +14.2K

Biggest sellers in Q2 2026

M3F, Inc. SOLD OUT −24.6K
Millennium Management LLC SOLD OUT −11.5K

Who is planning to sell?

No insider has filed a notice of proposed sale (Form 144) for Winchester Bancorp Inc in the last 12 months.

Is your stake being diluted?

Diluted share count, FY2025–FY2026

+0.1%

+0.11% a year

Each share's claim on the business

−0.1%

shrank without buying or selling a share

Spent on buybacks vs paid in stock

$3.35M vs —

over 2 fiscal years

Diluted shares, split-adjusted

Buybacks Stock-based comp

How patient are the owners?

Institutional shares by how long they've been held

5+ years0% 3–5 years0% 1–3 years78% Under 1 year22%

Quarterly turnover

6.3%

of institutional shares changed hands

Top 10 managers, median time held

1 year

Super Investors

Investment managers reporting WSBK on Form 13F

Holder	Shares	% of company	Change vs last qtr	Held since	% of their book
MP Mangrove Partners Im, LLC	186.2K	2.00%	Unchanged	2025	0.2%
Shares held by quarter Peak holding186.9K (Q3'25) Change over 8 quarters+186.2K Share of the company2.000% Mangrove Partners Im, LLC's full portfolio →
VC Vanguard Capital Management LLC	178.9K	1.93%	−2.6K (−1.4%)	2025	0.0%
Shares held by quarter Peak holding181.5K (Q1'26) Change over 8 quarters+178.9K Share of the company1.930% Vanguard Capital Management LLC's full portfolio →

Mangrove Partners Im, LLC

186.2K

% of company

2.00%

Change vs last qtr

Unchanged

Held since

2025

Vanguard Capital Management LLC

178.9K

% of company

1.93%

Change vs last qtr

−2.6K (−1.4%)

Held since

2025

22 more super investors behind a free account

See every manager holding Winchester Bancorp Inc, how their position has changed, and how long they've held it.

Institutional Funds

Mutual funds and ETFs reporting WSBK on Form N-PORT; together they hold 2.3% of the company

Fund	Position value	Shares	% of company	% of the fund	As of
VT Vanguard Total Stock Market Index Fund Vanguard Index Funds	$1.74M	132.1K	1.42%	0.00%	June 30, 2026
VE Vanguard Extended Market Index Fund Vanguard Index Funds	$585K	44.5K	0.48%	0.00%	June 30, 2026

Vanguard Total Stock Market Index Fund

Vanguard Index Funds

Position value

$1.74M

% of company

1.42%

% of the fund

0.00%

As of

June 30, 2026

Vanguard Extended Market Index Fund

Vanguard Index Funds

Position value

$585K

% of company

0.48%

% of the fund

0.00%

As of

June 30, 2026

7 more funds behind a free account

See every fund holding Winchester Bancorp Inc and how much of the fund the position is.

Insiders and 5%+ holders

From Forms 3/4/5 and Schedules 13D/G

Holder	Shares	% of company	Change vs last qtr	8 quarters	Held since	% of their book
WB Winchester Bancorp, MHC 5%+ holder 13D · 55.0%	5.1M	55.00%	—	—	—	—
This holder reports through Schedule 13D/G, not a quarterly 13F. Share of the company55.000% Disclosed stake13D · 55.0% View the 13D/G filing →
PC Pierce Connolly Carole Ann Insider	75.0K	0.81%	—	—	—	—
Insider holdings come from Form 3/4/5 filings, which are not quarterly. Share of the company0.810% Pierce Connolly Carole Ann's insider activity →

Winchester Bancorp, MHC

5%+ holder13D · 55.0%

5.1M

% of company

55.00%

Change vs last qtr

—

Held since

—

Pierce Connolly Carole Ann

Insider

75.0K

% of company

0.81%

Change vs last qtr

—

Held since

—

14 more holders behind a free account

See every insider and 5%+ holder of Winchester Bancorp Inc.

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