Bermuda-based White Mountains Insurance Group, Ltd. said it will buy back up to 1 million shares.

White Mountains, like Berkshire Hathaway, does not split its shares. They are currently trading at over $600, pricing the buy-back at around $600 million, if all of the authorised number of shares are bought. The Company intends to fund any repurchases with available cash.

Separately, Aon Corp., the world's second-largest insurance broker, said it would buy back as much as $1 billion of the company's shares.Aon has already repurchased $861 million shares under an earlier programme allowing as much as $1 billion in buybacks, the Chicago-based company said yesterday.

Using Friday's closing price of $35.31, the new programme would buy as many as 28.3 million shares, or 9.1 percent of the shares outstanding as of September 30.