Excerpted from “Day Traders 2.0: Wired, Angry and Loving It”,

The New York Times, March 26, 2010

The great mass of studies point to the same conclusion: trading is hazardous to your wealth, as an academic paper memorably put it. The losers far outnumber the winners.

Exactly how far is clear from one of the most comprehensive looks at the subject in a yet-to-be-published study conducted in Taiwan. (The country is ideal for this kind of research because all trades go through one place, the Taiwan Stock Exchange, which is willing to share the information.) The authors sifted through tens of millions of trades, from 1992 to 2006, and found that 80 percent of active traders lost money.

“More importantly, we found that if you were to look at the past performance of these traders, only 1 percent of them could be called predictably profitable,” says a co-author, Brad M. Barber, a finance professor at the University of California, Davis. Everyone else, it seems, was on a short-term winning streak. Even those who did modestly well found that their profits were wiped out, and then some, by transaction fees like commissions and taxes.

“It’s not impossible to make money actively trading,” Mr. Barber continues. “There are slivers of people out there who are quite good. And everyone thinks they will be in that group of 1 percent.”

So why do people persist in this line of work?

“The technical term is thrill-seeking,” says Hersh Shefrin, a professor of behavioral finance at Santa Clara University in California and author of “Beyond Greed and Fear,” an exploration of investors’ mindscapes. “There’s an adrenaline rush.