May 12 - Using "dark pools" to trade big blocks of stock without triggering ripples in the share price is booming in popularity. On Wall Street traders jockey to buy and sell shares of stock every day...but many of the big money trades are happening far away from the trading floor.

When pension funds and hedge funds want to sell or buy shares...usually thousands at a time...they prefer to do it anonymously....and usually.. on an electronic trading system. These so called "dark pools" are changing the face of trading but could systems designed to make trading more efficient have the opposite effect? Ruben Ramirez reports from New York.