Abercrombie & Fitch Co. rose the most in six months as it boosted its buyback authorization by 10 million shares to 22.9 million and posted profit excluding some items of 19 cents a share, a cent higher than it had forecast. Net income fell 52 percent to $15.5 million from a year earlier. The stock lost 15 percent Aug. 2 but led the S&P 500 up Wednesday.