Back in May, a small US broker-dealer said that dark pools might not be as dark as they purported to be. The firm produced a white paper which showed that participants could use some of the information published by dark pools to identify the direction and longevity of supposedly anonymous resting orders.
In Europe, another broker-dealer brought the issue to the attention of their buyside clients, who demanded that problem be addressed. The affected venues were forced to amend their data feeds - which they did within days.