It was the year that dark trading became the victim of its own success. While activity in off-exchange venues reached record levels in both the US and Europe, regulators across the globe have rounded on the phenomenon. American and EU regulators are working on tighter rules, while their counterparts in Canada and Australia have already clamped down.

Their concern is not mistimed. The activity ideally suited to dark pools of liquidity is very large single trades, which are rising in volume as stability returns to the equities market. For an institution seeking to sell a block of securities so large it would depress the price if placed on a traditional, "lit", stock exchange, the alternative is to place it with an operator who will execute it "in the dark", electronically allocating it among buyers without announcing the identity of the seller, the size of the trade or the price.