A Canadian consortium believes it has enough support to stymie the London Stock Exchange's takeover bid for TMX Group , Canada's largest stock market operator, at a shareholder vote on Thursday, a source with the 13-member consortium said.

Based on conversations with large shareholders who have indicated how they will vote, the Maple Group source said the consortium of banks, pension funds and financial services firms expected more than 1/3 of TMX shareholders to oppose the LSE offer. The deal needs a 2/3 majority to pass.

All I can say right now is we remain confident that we will get the vote, which is more than one third, said the source, who has no access to proxy votes submitted ahead of Thursday's 10 a.m. EDT (1400 GMT) shareholder vote.

TMX shareholders are due to vote on Thursday on a friendly C$3.6 billion offer from the LSE, and they can also officially rebut a hostile, C$3.8 billion bid from Canada's Maple Group.

Proxy advisory firms recommend the LSE bid, but investors have had a difficult time choosing between the cash-rich Maple deal and an LSE offer that's almost all in stock.

A Yes vote kills Maple's offer and leaves the LSE's friendly takeover in regulators' hands. A No vote would let Maple submit its C$50/share offer to its own shareholder vote.

The LSE offer is worth C$49 a share, including a C$4 dividend to TMX shareholders.

The Maple Group, officially formed in May, began to take root soon after the LSE bid for TMX in February and promised to create a transatlantic powerhouse of mining and energy equity.

The Maple Group, whose all-Canadian members include four major banks, five huge pension funds and North America's top life insurer, says in an unashamedly nationalistic proposal that it will keep a crucial domestic asset in Canadian hands.

(Reporting by Pav Jordan; editing by Janet Guttsman)