Summary
Updated Aug 31, 2026
MITSUI SUMITOMO INSURANCE CO LTD files SEC Form 4 reports at BERKLEY W R CORP (WRB). 20 SEC Form 4 filings on record going back to 2025, most recently on 4 March 2026. Most recent open-market trade: bought $5.31M of WRB on 4 March 2026. Lifetime open-market purchases: $705.46M. Historical track record: 3/5 stars across 94 tracked purchases.
Recent Transactions
20Every recent SEC Form 4 transaction MITSUI SUMITOMO INSURANCE CO LTD has reported, most recent first.
Track Record
InsiderAlpha computes a forward-return-based score for every insider with enough Form 4 purchase history. The metrics below reflect realized performance after each tracked open-market purchase.
| Metric | Value |
|---|---|
| InsiderAlpha rating | ★★★☆☆ (3/5) |
| Total purchases tracked | 94 |
| Purchases with forward-return data | 94 |
| 30-day win rate | 41% |
| 90-day win rate | 2% |
| Avg 5-day return | -0.09% |
| Avg 30-day return | -0.95% |
| Avg 90-day return | -4.57% |
| Best 30-day return | +7.30% |
Trading Pattern
InsiderAlpha's records for MITSUI SUMITOMO INSURANCE CO LTD go back to 2025: 20 primary Form 4 filings, an average of 10.0 per year. The typical open-market purchase is $7.50M (94 buys totaling $705.46M). The largest single buy on record is $22.26M of WRB in 2026. 94 recorded transactions carry a Rule 10b5-1 flag, meaning they were pre-scheduled under a written trading plan rather than discretionary.
Other Insiders Active in the Same Sector
No other insider has filed at MITSUI SUMITOMO INSURANCE CO LTD's companies, so these are insiders reporting open-market trades at other companies in the same sector.
- Anchorage Lending CA, LLC - $20.19M of ABTC open-market activity in the last 12 months
- John M. Pasquesi - $19.97M of ACGL open-market activity in the last 12 months
- Christopher J. Meade - $19.94M of BLK open-market activity in the last 12 months
- James Matthew Darden - $19.92M of GL open-market activity in the last 12 months
- AMERICAN INTERNATIONAL GROUP, INC. - $1.80B of CRBG open-market activity in the last 12 months
- SUMITOMO MITSUI FINANCIAL GROUP, INC. - $1.31B of JEF open-market activity in the last 12 months
More Notable Insiders
Other corporate insiders with significant SEC Form 4 track records on InsiderAlpha:
Frequently Asked Questions
What is MITSUI SUMITOMO INSURANCE CO LTD?
MITSUI SUMITOMO INSURANCE CO LTD is a corporate entity of BERKLEY W R CORP (WRB). InsiderAlpha holds 20 primary Form 4 filings for it, the earliest from 2025, updated as new SEC EDGAR filings are processed.
When did MITSUI SUMITOMO INSURANCE CO LTD last file a Form 4?
The most recent primary Form 4 on record is dated 4 March 2026, one of 20 filings going back to 2025.
Has MITSUI SUMITOMO INSURANCE CO LTD been buying or selling stock?
Recorded transactions: 94 open-market purchases ($705.46M) and 0 open-market sales across all tracked filings.
How accurate is MITSUI SUMITOMO INSURANCE CO LTD's historical track record?
Across 94 tracked purchases, MITSUI SUMITOMO INSURANCE CO LTD averaged -1.0% avg 30-day return with a 41% 30-day win rate. InsiderAlpha rates the track record at 3/5 stars.
Where can I see all of MITSUI SUMITOMO INSURANCE CO LTD's SEC filings?
All Form 4 filings, transaction values, and 10b5-1 plan flags are listed on this page and updated in real time as new SEC EDGAR filings are processed.
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