The three largest dark pools in the U.S. are run by Credit Suisse, Barclays and UBS AG, according to Finra. Combined commissions for the three venues, based on executed trades, was $800 million in 2013, according to estimates by Tabb Group. There are a number of smaller dark pools that are either independently owned or controlled by consortia of banks, but they typically represent a small percentage of daily trading volume of stocks.