A group of big Canadian banks and pension funds bidding for TMX Group are in talks to lure at least three, and possibly four, other financial services firms to join their consortium, according to a person familiar with the situation.

The consortium, Maple Group Acquisition Corp, last month unveiled a counterbid for TMX in an effort to upset a merger deal struck between TMX and London Stock Exchange Group, announced in February. TMX shareholders are due to vote on that proposed tie-up later this month.