** Shares of commercial insurer W.R.Berkley WRB.N up 14.2% to $75.82

** WRB hits record high and is the highest gainer on S&P 500 .SPX index

** Co confirms Mitsui Sumitomo Insurance $(MSI)$ entered into an arrangement with the Berkley family and intends to purchase 15% of WRB's shares in open market or private transactions from third parties

** Berkley family will not be selling any of its common stock to MSI, nor will MSI purchase any shares from WRB

** MSI's investment is anticipated to be completed by end of March 2026

** Including session's move, WRB up 29.6% YTD; it rose 26.5% in 2024

(Reporting by Sukriti Gupta in Bengaluru)

((Sukriti.Gupta@thomsonreuters.com;))