By John McCrank – When the average investor, or even a big portfolio manager, tries to buy or sell shares now, the trade is often matched up with another order by a dealer in a so-called “dark pool,” or another alternative to exchanges.
The pools were originally created for institutions to trade large blocks of stock without creating a large impact in the market. If an order of 1 million shares was tracked, people on the other side of the trade could quickly jack up prices and the original investor could easily pay more than expected.
But much of the trading isn’t like that now – the average size of orders in dark pools has shrunk to around 200 shares, similar to levels on public exchanges. more> http://tinyurl.com/kjyr5qq