OMAHA, Neb.—Berkshire Hathaway Inc. reportedly made a $1.7 billion cash offer for Bermuda-based reinsurer IPC Holdings Ltd. but was rejected.

Omaha, Neb.-based Berkshire is the unnamed “Party M” in regulatory filings outlining a July 1 bid for IPC, Bloomberg reported Thursday, citing two people with knowledge of the situation.

IPC rejected the offer because “Party M” didn’t want IPC to pay a third-quarter dividend, according to the regulatory filings that also outlined the lesser stock-and-cash offer that IPC eventually accepted from Validus Holdings Ltd.

Validus and IPC last week announced their merger agreement after IPC accepted a sweetened offer from Validus valued at $1.65 billion in cash and stock. Validus boosted the cash component of its offer to $7.50 a share, more than twice its previous cash offer.

In addition, “Party M” had offered $30 a share and would have required IPC to pay a $50 million inducement fee, Bloomberg reported.

IPC, which was the target of a months-long bidding war, said it was considering other suitors after its shareholders in June rejected a planned merger with Max Capital Group Ltd. Another Bermuda-based rival, Flagstone Reinsurance Holdings Ltd., had offered $1.74 billion in cash and stock for IPC.

According to Bloomberg, IPC also had offers from a “large private equity firm” and a reinsurer that regulatory filings described as “Party N.”

A spokeswoman for IPC declined to comment, citing confidentiality agreements signed during negotiations. A spokesman for Validus also declined to comment.

Ajit Jain, the Stamford, Conn.-based president of Berkshire’s reinsurance group, also declined to comment.

IPC, formed in 1993 in wake of Hurricane Andrew, specializes in short-tail property catastrophe reinsurance. The firm has been under pressure to diversify its monoline model and attracted several suitors because it was trading below book value, analysts said.

Shareholders of IPC and Validus have yet to formally approve their merger.