The Maple Acquisition Group has again extended its almost $4-billion bid for the TMX Group, operator of Canada's major stock markets, this time until the end of July.   

The acquisition group, made up of 13 of Canada's largest financial institutions, said Thursday that its $50 per share bid is now good until  5 p.m. ET on July 31 unless further extended or withdrawn.   

Maple seeks to acquire a minimum of 70 per cent and a maximum of 80 per cent of the shares of TMX Group as part of an integrated transaction valued at about $3.8 billion.   

Under the deal, Maple investors would end up holding 60 per cent of the TMX Group's stock and current TMX shareholders 40 per cent.   

The latest previous deadline had been May 31, however, the acquisition group said earlier this month it would extend the expiry date until July 31 "if necessary to obtain the required regulatory approvals."   

Securities regulators are currently reviewing the proposed takeover and its merger with the alternative Alpha trading platform and CDS clearing house.   

Maple is comprised of the Alberta Investment Management Corporation, Caisse de depot et placement du Quebec, Canada Pension Plan Investment Board, CIBC World Markets Inc., Desjardins Financial Group, Dundee Capital Markets Inc., Fonds de solidarite des travailleurs du Quebec (F.T.Q.), GMP Capital Inc., National Bank Financial & Co. Inc., Ontario Teachers' Pension Plan, Scotia Capital Inc., TD Securities Inc. and The Manufacturers Life Insurance Company.