WTM

White Mountains Insurance GP Cross-source read$2,046 0.54%
FinancialsCUSIP G9618E107· EOD Sep 15, 2026

Among active 13F managers last quarter, 6 opened and 26 added, while 19 reduced; the largest holder to move was Neuberger Berman Group LLC (−3.8%). No open-market insider trades in the last 180 days.

Tracked 13F holders
317
208 in Q2 2026 filings
13F value (tracked)
$4.5B
Smart-money readBullish
Net sellingNet buying
Funds · active managers, latest 13F
32 adding · 19 trimming
Insiders · Form 4 open-market, 180d
0 buying · 0 selling
US House · STOCK Act, 180d
0 buying · 0 selling

Funds lean in and no leg opposes.

Price & smart-money activity

$2,046 0.54%5Y +91.5%
$892.29$1,275$1,659$2,042$2,42520212022202320242025202625252334223225352233830303729273929305383737394038413861375453615370553797987715066
Hover for who · click for detailEnd-of-day closing prices52w $1,651 – $2,319

Who owns WTM?

317 tracked 13F filers · ranked by shares held

317 tracked 13F filers disclose a position in WTM as of the latest SEC 13F filings, a combined $4.5B in reported value. Holders and values reflect the 13F filers Arkolith currently tracks, not the entire institutional universe. Counts and totals are a floor, not the full institutional ownership.

#FundSharesPosition valueLast moveAs ofHistory
1Dimensional Fund Advisors LP157K
$344.1M
~0%
Added · +14 sh
Q1 2026
2Neuberger Berman Group LLC125K
$274.0M
−3.8%
Reduced · −5K sh
Q1 2026
3River Road Asset Management, LLC121K
$264.8M
−0.3%
Reduced · −361 sh
Q1 2026
4BlackRock, Inc.118K
$244.4M
+4.0%
Added · +5K sh
Q2 2026
5Vanguard Portfolio Management LLC112K
$232.2M
−3.1%
Reduced · −4K sh
Q2 2026
6Vanguard Capital Management LLC107K
$222.8M
−1.5%
Reduced · −2K sh
Q2 2026
7Cooke & Bieler LP105K
$230.4M
−1.6%
Reduced · −2K sh
Q1 2026
8Fuller & Thaler Asset Management, Inc.102K
$211.3M
−2.5%
Reduced · −3K sh
Q2 2026
9Fiduciary Management Inc85K
$186.9M
−5.8%
Reduced · −5K sh
Q1 2026
10Wallace Capital Management Inc.80K
$166.0M
+1.6%
Added · +1K sh
Q2 2026
11Morgan Stanley59K
$130.3M
−28%
Reduced · −23K sh
Q1 2026
12Gendell Jeffrey L59K
$122.8M
+57%
Added · +21K sh
Q2 2026
13Boston Partners57K
$126.2M
−25%
Reduced · −19K sh
Q1 2026
14London Co Of Virginia54K
$112.1M
−5.4%
Reduced · −3K sh
Q2 2026
15State Street Corp50K
$104.2M
+2.2%
Added · +1K sh
Q2 2026
16Geode Capital Management, LLC49K
$102.5M
+17%
Added · +7K sh
Q2 2026
17Reinhart Partners, LLC.37K
$82.1M
−15%
Reduced · −7K sh
Q1 2026
18T. Rowe Price Investment Management, Inc.34K
Withheld
−18%
Reduced · −7K sh
Q2 2026
19Norges Bank32K
$66.9M
+5.5%
Added · +2K sh
Q4 2025
20Bank Of America Corp28K
$62.3M
−1.6%
Reduced · −451 sh
Q1 2026
21Cannell & Spears LLC28K
$57.2M
−1.6%
Reduced · −450 sh
Q2 2026
22Charles Schwab Investment Management Inc24K
$53.3M
+4.3%
Added · +1K sh
Q1 2026
23Raymond James Financial Inc24K
$52.6M
−0.1%
Reduced · −18 sh
Q1 2026
24Mraz, Amerine & Associates, Inc.22K
$46.1M
+0.2%
Added · +39 sh
Q2 2026
25Allspring Global Investments Holdings, LLC18K
$37.4M
−2.7%
Reduced · −496 sh
Q2 2026

Holders and values reflect the 13F filers Arkolith currently tracks, not the entire institutional universe. Counts and totals are a floor, not the full institutional ownership. 1 value row is withheld because the reported units disagree with same-security peers; share counts are unchanged.

Is WTM being bought or sold by institutions?

Last quarter, 6 funds opened a new position in WTM and 26 added to an existing one, while 19 reduced. Based on 13F filings from active, signal-eligible managers (passive index funds and other mechanical holders are excluded from this count).

Opened
6
funds took a first position
Added
26
added to an existing position
Reduced
19
reduced, still holding
Biggest moves · ranked by size of the change, positions above a floor

Funds that own WTM also own

CompanyCo-held byTheir position there
Microsoft CorpMSFT173 funds$217.4B
Alphabet Inc-CL AGOOGL169 funds$146.8B
Amazon.com IncAMZN168 funds$168.2B
Apple IncAAPL167 funds$246.9B
Alphabet Inc-CL CGOOG167 funds$112.1B
JPMorgan Chase & CoJPM167 funds$54.7B
Nvidia CorpNVDA166 funds$337.5B
Berkshire Hathaway Inc-CL BBRK/B165 funds$32.8B
Eli Lilly & CoLLY164 funds$70.9B
Johnson & JohnsonJNJ164 funds$41.8B
Chevron CorpCVX162 funds$24.3B
Meta Platforms Inc-Class AMETA161 funds$91.3B

Ranked by how many of WTM's tracked holders also hold each name. The last column is those co-holders' combined reported position in that name, not in WTM.

Insider activity (Form 4)

Full insider page →
Net · 180d
$0
0 open-market transactions
DateInsiderRoleActionSharesValue
Dec 19, 2025Rountree George ManningChief Executive Officer, DirectorSell (S)5K$10.3M
Dec 19, 2025Campbell Reid TarltonDirectorSell (S)5K$10.3M
Dec 16, 2025Gelston Philip ADirectorSell (S)165$338K
Nov 17, 2023Hicks Weston MDirectorBuy (P)
5 lots, same day
1K$1.5M
Dec 22, 2022Hildreth MichaelaMD & Chief Accounting OfficerSell (S)100$137K
Sep 20, 2022Davis Morgan WDirectorSell (S)945$1.3M
Sep 20, 2022Carlson Peter MDirectorSell (S)200$280K
May 31, 2022Hildreth MichaelaMD & Chief Accounting OfficerSell (S)100$127K
Feb 9, 2021Davis Morgan WDirectorSell (S)
2 lots, same day
2K$1.7M
Mar 24, 2020Davis Morgan WDirectorBuy (P)
3 lots, same day
1K$795K
Dec 10, 2019Smith Lowndes AndrewDirectorSell (S)200$221K
Aug 8, 2019Smith Lowndes AndrewDirectorSell (S)
2 lots, same day
1K$1.1M

One row per insider, day and transaction code; shares and value are summed across the lots. Every lot is on the full insider page and in the filing.

Do institutions, insiders and Congress agree?

Mixed signals

Where institutional funds (13F), corporate insiders (Form 4) and US House members (STOCK Act) are buying or selling the same name in the same window. Green is buying, red is selling.

SEC EDGAR 13F + Form 4 + US House STOCK Act{ }get_ticker_confluence · API & MCP

Signals by source

Insiders and Congress: last 180 days. Funds: latest 13F, top 100 holders incl. passive

SourceBuyingSellingNet
13F funds
Top 100 holders by value, passive included; the hero counts active managers only
4839
Insiders
Form 4 open-market
00$0
US House
STOCK Act trades
00$0
Sector rotation
WTM is in Financials, which smart money is rotating OUT OF
$30.6B

Capital Rotation reports where institutional capital disclosed rotating, as of the latest public SEC 13F filings. It is data, not investment advice, a recommendation, or a prediction. Filings lag about 45 days and cover long US equity positions only. Past disclosed flows do not indicate future prices. Do your own research; consult a licensed advisor.

Institutional ownership over time

208 tracked filers in Q2 2026 filingsstill filing
0161322Q3 2024Q1 2025Q3 2025Q1 2026Q2 2026
tracked filers holding their reported valueQ2 2026 filings so far: $2.0B · 2 values withheld
Each bar counts tracked filers with a position in that quarter's filings, so the newest bar excludes filers still on an earlier quarter. Arkolith's tracked universe has grown over this window; part of any long-run rise is coverage, not new buyers.

Recent filings

15 most recent

Keep exploring

Connected entities for WTM

Browse more

Build

Ask your agent what changed in WTM

This stock page is the public Follow view. For one current, evidence-backed answer, use capital_change_brief through REST or MCP. It compares tracked 13F changes with qualifying Form 4 activity and cites the SEC evidence.

Copy-paste
curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://arkolith.com/api/v1/stocks/WTM/capital-change-brief"
Ask your agent
Use Arkolith's capital_change_brief for WTM.
Tell me what changed, whether insider activity
corroborates it, and cite the SEC evidence.

13F holdings + Form 4 insider transactions + end-of-day price history + the live filing stream, joined for WTM. Filings are public domain, sourced to SEC EDGAR; price series derived from end-of-day closes.