Another day another deal. BATS Global Markets, operator of the third largest stock exchange in the US, is on the verge of a merger with Chi-X Europe to create the largest platform for share trading in Europe by volume. This follows swiftly the London Stock Exchange’s tie-up with TMX of Canada and NYSE Euronext and Deutsche Börse's merger. Jeremy Grant, FT Trading Room editor, discusses with Philip Stafford, the logic behind this latest marriage and who might be next.