The London Stock Exchange response to bidder Deutsche Boerse's proposal for a lower acceptance threshold that will ensure the deal goes through.
"No decision has been made in this regard yet," LSE said in a statement today. The decision will be made today when the facts "will be finally evaluated by the parties involved", it added.
The German stock exchange wants to cut the shareholder voting target to 60 per cent, down from 75 per cent, to allow index funds to participate.
LSE shareholders about a week ago voted almost unanimously in favour of the tie-up.
Deutsche Boerse shareholders have until midnight on 12 July to approve the deal, but it would still face several regulatory hurdles before it can complete.
Sources have warned City A.M. that the merger could see the headquarters of the newly created business leave the UK, despite previous pledges that a joint HQ would remain in London.
Spokesmen for the London Stock Exchange and Deutsche Boerse declined to comment.