Security key
G9618E107
WHITE MOUNTAINS INSURANCE GROUP LTD - COMMON (WTM)
CUSIP: G9618E107
Q1 2018 13F Holders as of 31 Mar 2018
- Security type / class
- Equity / COMMON
- Total 13F shares
- 3,186,982
- Total 13F value
- $2,621,416,419
- Share change
- +62,427
- SEC-reported price per share
- $822.52
- Number of holders
- 229
- Value change
- +$51,033,745
- Number of buys
- 106
- Number of sells
- 85
- Shares outstanding
- 2,481,286
Holder snapshot
6 signals
Security identity
Names, identifiers, and filing context for this profile.
1 source field
Report period
Q1 2018
Institutions
229
Top holders
10
WTM full security history
Ownership snapshot
Full 13F holder table
Newer quarter: Q3 2025
WHITE MOUNTAINS INSURANCE GROUP LTD SEC filings
WHITE MOUNTAINS INSURANCE GROUP LTD company facts
WHITE MOUNTAINS INSURANCE GROUP LTD 13D/G history
Broader feeds
Reporting periods
Holder history for CUSIP G9618E107
Recent filing periods:
Ownership snapshot
Top reported holders of WTM - WHITE MOUNTAINS INSURANCE GROUP LTD - COMMON (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
VANGUARD GROUP INC
Disclosed value leader
VANGUARD GROUP INC
Comparable rows
15/15
Latest evidence
31 Dec 2017
13F
Lead comparable stake: 12%
Showing 1-6 of 15 holder rows.
Quick read
VANGUARD GROUP INC leads the comparable SEC ownership view at 12%.
15 of 15 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens VANGUARD GROUP INC's linked filing trail.
Comparable ownership
Top 5
VANGUARD GROUP INC
12%
PRICE T ROWE ASSOCIATES INC /MD/
11%
WELLINGTON MANAGEMENT GROUP LLP
7.1%
FULLER & THALER ASSET MANAGEMENT,...
6.9%
Boston Partners
6.5%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-6 of 15 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| VANGUARD GROUP INC |
13F
Company
|
12%
|
$245,021,000
287,826 shares
|
— | 31 Dec 2017 |
| PRICE T ROWE ASSOCIATES INC /MD/ |
13F
Company
|
11%
|
$235,060,000
276,125 shares
|
— | 31 Dec 2017 |
| WELLINGTON MANAGEMENT GROUP LLP |
13F
Company
|
7.1%
|
$150,973,000
177,348 shares
|
— | 31 Dec 2017 |
| FULLER & THALER ASSET MANAGEMENT, INC. |
13F
Company
|
6.9%
|
$146,510,000
172,105 shares
|
— | 31 Dec 2017 |
| Boston Partners |
13F
Company
|
6.5%
|
$137,446,000
161,459 shares
|
— | 31 Dec 2017 |
| BlackRock Finance, Inc. |
13F
Company
|
6.2%
|
$131,093,000
153,994 shares
|
— | 31 Dec 2017 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
13F holder rows
Institutional holders as of Q1 2018
Investor-level positions for this CUSIP, loaded as an interactive table.
Institutions
229
Shares
3,186,982
Rows available
229
| Investor | Option | Weight % | Change % | SEC-reported value | * Price | Shares | Share Change | Activity | Report Period |
|---|
* SEC-reported price is the security price as of the portfolio date and can indicate the last known price at which the security was still held. The marker flags a reported price that did not pass the local price check.
Compare Q1 2018 vs Q4 2025 Across Filers
Q4 2025 holders
353
Q1 2018 holders
229
Holder diff
-124
| Investor | Q4 2025 Shares | Q1 2018 Shares | Share Diff | Share Chg % | Q4 2025 value | Q1 2018 value | Value change | Value Chg % |
|---|
Trend: ostatnie 8 kwartałów (+ wybrane okresy porównania).
Quarterly Holders Trend
Quarterly Value Trend
Quarterly Shares Trend