Hilton Hotels Corp., which has seen its stock decline by nearly two-thirds over the past year, said Friday that it plans to buy up to 6 million of its 48 million shares of common stock.

Hilton's board had previously granted management the authority to purchase the shares, which can be extended beyond this year if conditions warrant.Hilton shares rose 87.5 cents to $30.25 a share Friday on the New York Stock Exchange.

The stock was trading at more than $100 a share last year after the company, which owns, operates or franchises more than 270 hotels and casinos, put itself up for sale.

The value of the stock began declining after it became apparent that Hilton would not be able to find a buyer to meet its asking price, which analysts believe was as much as $4.5 billion.