NEW YORK (Bloomberg) — Warren Buffett, who cut back sales of protection to insurers because prices were too low, is betting on a rate increase by investing in the only two firms to write more reinsurance than his Berkshire Hathaway Inc.

Buffett has more than $4.5 billion invested in Munich Re and Swiss Reinsurance Co., choosing to put Berkshire's cash in two companies that account for more than a third of the global market instead of using the money to compete against them.

Had Buffett, as Berkshire's chairman and chief executive officer, directed a part of that capital to his own underwriters, he could have pushed down the price of coverage, analysts said.

"This is a move to increase that exposure without disrupting the pricing," said Craig Fehr of Edward Jones & Co., who has a "hold" rating on Omaha, Nebraska-based Berkshire's stock. "It's likely a reflection of the fact there aren't an abundance of opportunities to write new business."