The Chinese have caught day-trading fever, sending the Shanghai Stock Exchange into the stratosphere. The first two weeks of January saw trading volumes at $154 billionmore than one-fifth of the volume for all of last year, which was triple that of the year before. When I go to the beauty salon, even the girls who give me a manicure are talking about stocks! consultant Shirley Lei told The New York Times. The enthusiasm alarms regulators. Exchange officials warned that the online trading systems might collapse under the volume, while bank officials said they would refuse loans to people who intended to buy stocks.