Market participants voiced concern Thursday that the Nikkei stock average may fall below the 13,000 line as foreign investors flee the Japanese market and shift their cash to more attractive emerging economies instead.

The 225-issue Nikkei average rose 278.94 points Thursday to close at 13,783.45 on the Tokyo Stock Exchange, recouping some of the losses of the past four trading days. The index tumbled 468.12 points Wednesday to end at its lowest level since October 2005.

"The speed of the stock fall is too fast," lamented Haruki Takahashi, general manager of retail equities at Mitsubishi UFJ Securities Co. "The Nikkei average has dropped more than 2,000 points since the end of last year."