Berkshire buys $1.2 bln in stock from single investor

Berkshire also raised the threshold for future share buybacks to 120 percent of book value from 110 percent - the level it chose when it first approved a repurchase program in September 2011.

The most recent buyback was done at slightly more than 117 percent of Berkshire's Sept. 30 book value.

Berkshire said it bought 9,200 Class A shares from "the estate of a long-time shareholder," whom it did not name.

Buffett's assistant did not immediately respond to a request for comment on the shareholder's identity.

According to Thomson Reuters data, only seven individuals or entities control enough stock to have been the seller, Buffett among them. It is possible the shareholder's investment was not publicly known.

The repurchase came less than a month ahead of the looming "fiscal cliff," the automatic steep tax hikes and spending cuts set for Jan. 1 that the White House and members of Congress have been negotiating to avoid.

Among other levies, the estate tax is expected to rise in the new year package, which may have spurred the anonymous shareholder to sell now.

Buffett himself was one of the signers of an open letter released on Tuesday that called for a lower threshold on the tax and a higher taxation rate.

"We believe it is right to have a significant tax on large

... contd.