MITSUI SUMITOMO INSURANCE CO LTD - 04 Dec 2025 SCHEDULE 13D Report for W. R. BERKLEY CORPORATION Common Stock, par value $0.20 per share (WRB)

Filing Manager
MITSUI SUMITOMO INSURANCE CO LTD
Reporting Manager
Mitsui Sumitomo Insurance Co., Ltd.
Security
W. R. BERKLEY CORPORATION Common Stock, par value $0.20 per share
Symbol
WRB
Shares outstanding
379,699,906 shares
Disclosed Ownership
48,601,588 shares
Ownership
13%
Form type
SCHEDULE 13D
Filing time
11 Dec 2025, 17:03:26 UTC
Date of event
04 Dec 2025
Next filing
14 Jan 2026
SEC
View on sec.gov

Quoteable Key Fact

"MITSUI SUMITOMO INSURANCE CO LTD disclosed 13% ownership in W. R. BERKLEY CORPORATION Common Stock, par value $0.20 per share (WRB) on 04 Dec 2025."

Quick Takeaways

  • MITSUI SUMITOMO INSURANCE CO LTD filed SCHEDULE 13D for W. R. BERKLEY CORPORATION Common Stock, par value $0.20 per share (WRB).
  • Disclosed ownership: 13%.
  • Date of event: 04 Dec 2025.

What Changed

  • No earlier schedule filing is available for direct comparison.
  • Current filing was accepted on 11 Dec 2025, 17:03.

Why This Matters

  • This page explains what this Schedule 13D/13G filing tells you before manager-level rows.
  • You can verify ownership claims directly against the original SEC filing.

Source Evidence

Backed by Schedule 13D/13G

Beneficial ownership values are sourced from the original SEC Schedule 13D/13G filing.

See Original Filing

Reporting Managers (2)

Name Ownership Shares Owned sole voting power shared voting power Signature Title CIK
Mitsui Sumitomo Insurance Co., Ltd. 13% 48,601,588 48,601,588 0 /s/ Hironori Morimoto Hironori Morimoto/Authorized Signatory 0001142206
MS&AD Insurance Group Holdings, Inc. 13% 48,601,588 0 48,601,588 /s/ Hironori Morimoto Hironori Morimoto/Authorized Signatory 0001431048