Berkshire Hathaway Inc spent $1.2 billion buying back 9,200 of its Class A shares from the estate of a long-time investor, Warren Buffett's conglomerate said on Wednesday.

Berkshire, which operates a variety of companies in the insurance, energy, rail and utility sectors, bought the shares at a cost of $131,000 apiece and may buy more stock in the market at prices up to 120 percent of book value.

The stock repurchase was authorized by the board of directors, which raised the price limit for Berkshire's repurchases to the 120 percent of book value level.

Berkshire's Class A shares were up 0.5 percent at $131,500 in morning trading.