TMX Group's earnings tumbled in the second quarter on uncertain global markets, higher operating expenses, and costs related to its failed merger deal with London Stock Exchange as well as its proposed acquisition by Maple Group Acquisition Corp.

The Toronto-based exchange operator said it earned C$1.8 m (€1.5m), or 2 Canadian cents a share, down sharply from C$54.7m, or 73 Canadian cents, a year earlier.