The decision by a US judge to toss out a case brought against Barclays' dark pool is a rare public win for anonymous trading venues, which have been courting their fair share of controversy. But make no mistake, operators of these platforms may have won a battle, but they are still well and truly in the war.

The case that US District Judge Jesse Furman in New York threw out on August 26 alleged that Barclays, along with seven US stock exchanges, including the New York Stock Exchange and Nasdaq, manipulated their pools to the benefit of HFTs. Furman ruled the plaintiffs' suit had not alleged any actions that met the definition of "manipulative acts" or explained how those actions could have affected the price of stock trades.