Computers, Not Traders Now Make Vast Majority Of Wall Street Trades (VIDEO)

Computers are king, even on Wall Street.

Today, close to 70 percent of all the trades on Wall Street are conducted by high-frequency traders, or super-computers that can buy and sell stock faster than it takes for someone to blink, according to a segment airing on 60 Minutes on Sunday.

"Humans are not involved in the trading because humans are way too slow to trade on the kinds of opportunities that we're trying to capture," Tradeworx Chief Executive Manoj Narang says in the segment. "We're trying to capture opportunities that exist for only fractions of a second."

Defenders of high-frequency trading argue that the innovation helps the greater market by increasing both liquidity and volume, to the benefit not only the computer's operators but also long-term investors. Its detractors, on the other hand, say high-frequency trading acts as a form of insider trading that decreases confidence in the integrity of the system.

From the policy side, there are fears that high-frequency trading poses a threat to market stability. "What's the impact of that algorithm that has behaved in an unexpected way, on lots of other investors in the marketplace?" asks Securities and Exchange Commission chair Mary Shapiro.

The SEC's concern is well documented. After last month's flash crash, when the Dow Jones unexpectedly plummeted nearly 600 points and then rebounded within 15 minutes, the regulatory agency put much of the blame squarely on aggressive selling by a high-frequency trading computer.

Watch the 60 Minutes segment here: