Asian stocks fell, with the regional benchmark index heading for a three-week low, after Japan downgraded its assessment of the world’s third-biggest economy and as investors await indications of policy direction from the Federal Reserve. Nikkei 225 9,033.29 -52.10 -0.57% S&P/ASX 200 4,359.4 +15.70 +0.36% Shanghai Composite 2,073.45 +17.74 +0.86% China Southern Airlines Co. fell 3.6 percent in Hong Kong as Asia’s biggest carrier by passenger numbers reported first- half profit tumbled. Shikoku Electric Power Co. sank 10 percent in Tokyo after Credit Suisse Group AG rated the stock underperform. Aozora Bank Ltd. surged 14 percent after the Japanese lender unveiled a plan to repay a taxpayer bailout and buy back common stock.