"Nearly everyone on Wall Street is wondering how hedge funds and large banks like Goldman Sachs
are making so much money so soon after the financial system nearly collapsed.
High-frequency trading is one answer...
“This is where all the money is getting made,” said William H. Donaldson, former chairman and chief executive of the NYSE..
High-frequency traders often confound other investors by issuing and then canceling orders almost simultaneously.
Loopholes in market rules give high-speed investors an early glance at how others are trading...
In less than half a second, high-frequency traders gained a valuable insight: the hunger for Broadcom was growing.
Their computers began buying up Broadcom shares and then reselling them to the slower investors at higher prices...
The result is that the slower-moving investors paid $1.4 million for about 56,000 shares,
or $7,800 more than if they had been able to move as quickly as the high-frequency traders.
Multiply such trades across thousands of stocks a day, and the profits are substantial.
High-frequency traders generated about $21 billion in profits last year, the Tabb Group,
a research firm, estimates", http://www.nytimes.com/2009/07/24/business/24trading.html