Warren Buffett's Berkshire Hathaway Inc bids $3.2 bn for Transatlantic Holdings Inc.
Transatlantic's board said on Sunday it would "carefully consider and evaluate" the $52-per-share offer by Berkshire unit National Indemnity Co.
Buffett's bid tops two rival offers put before Transatlantic.
Transatlantic has an agreement to be bought by Allied World Assurance Company Holdings Ltd in a deal currently worth $44.22 per share, or $2.75 billion.
Validus Holdings Ltd, meanwhile, has launched a hostile bid for Transatlantic, with a proposal currently worth $46.36 per share, or $2.89 billion.