The London Stock Exchange and TMX Group are unlikely to sweeten the terms of their agreed merger, a person familiar with the matter said Sunday, despite the emergence of a rival bid from a consortium of Canada's biggest banks and pension funds.

TMX on Saturday said it had received a non-binding offer meant to form the basis of further discussions. People familiar with the situation said the consortium includes Toronto-Dominion Bank, Bank of Nova Scotia, Canadian Imperial Bank of Commerce and the National Bank of Canada, four of Canada's largest banks. Pension funds including Quebec's Caisse de depot et placement du Quebec, Fonds de solitarite FTQ, Alberta Investment Management, Ontario Teachers Pension Plan and Canada Pension Plan Investment Board, are also said to be part of the group.