Berkshire Hathaway on S&P Watch

NEW YORK (TheStreet) -- Berkshire Hathaway(BRK.A Quote) is in danger of losing its AAA rating by Standard & Poor's, after the company agreed to buy railroad Burlington Northern Santa Fe(BNI Quote).

"We believe that this transaction will decrease the liquidity and capital adequacy of the insurance operations," said John Iten, an S&P credit analyst, in a statement.

Warren Buffett's firm agreed to buy the railroad for $26 billion on Tuesday. The deal is valued at $44 billion in cash and stock, making it Berkshire's largest acquisition.

Berkshire's investments in Goldman Sachs(GS Quote), General Electric(GE Quote), WM. Wrigley Jr. and Swiss Re have also reduced insurance company liquidity, S&P said.

-- Reported by Jeanine Poggi in New York

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