The decision by the Office of Fair Trading yesterday to refer the proposed merger of Bats Global Markets and Chi-X Europe to an in-depth review by the UK's Competition Commission is likely to result in the shareholders of each company posing the question: what happens now?

The referral could delay the deal by up to six months; the Competition Commission has set December 2 as the date by which it will reports its findings, and may extend this by a further eight weeks if it deems there are "special reasons".