Fears that weaker US stocks will lead to more downward pressure on the US dollar is casting a pall over the shares of Asia's exporters, whose sales and profits in their biggest market will suffer. Japan, Hong Kong and South Korea led the rout, which brought Tokyo's Nikkei 225 Average down by more than 2% in early trade, and by the close of business it stood at 10,485.74, down 266.92 points.