Berkshire Hathaway Inc. bought back $928 million of its own stock during three weeks in August as Warren Buffett took advantage of a new policy that gives him more freedom to decide when repurchases are worth it.

A change in Berkshire’s repurchase policy announced in July spurred buybacks of both classes of the company’s stock in the third quarter. Berkshire’s chairman paid an average price of $312,806.74 to repurchase 225 Class A shares, and bought back more than 4 million Class B shares at an average price of $207.09, the company said in a regulatory filing Saturday.

While the 88-year-old investor has dabbled in repurchasing shares before, he’s long favored acquisitions of companies or investing in shares of other firms over capital return. Still, he’s struggled to find ways to invest a swelling cash pile that has surpassed $100 billion each of the past five quarters. The more relaxed buyback policy gives the billionaire another way to deploy money.

The firm’s old policy limited repurchases to when the shares traded at less than a 20 percent premium to book value. Now, Buffett and Vice Chairman Charlie Munger can decide when the stock is trading at less than what they believe is the intrinsic value.

A slump in Berkshire shares over the past month raises the question of whether Buffett has been buying back more stock. The shares have traded below his average purchase price for much of the past two weeks and the Class A stock closed Friday’s trading at $308,411.