Dark pools have been a success as an alternative trading mechanism. Institutions really crave the ability to trade anonymously and in bulk with few market ripples. We are entering version 2.0 of these services. Concerns about access and efficiency are cropping up. Let's face it, most traders do not want to have to check multiple services throughout the day. And a lot of services, beyond LiquidNet, ITG and Pipeline, are out there. Some firms are tinkering with "exclusive member" arrangements. Some are open access and some are available only via brokers. So there is a flowering of innovation at play. Most agree that volume will keep on rising. Currently, it's at about 10 percent. As volume has grown, the SEC has become curious. It is studying the market now.

For more:
- here's the article from Investment Dealers' Digest (For FierceFinance readers)