London Stock Exchange Group (LSE), whose shareholders overwhelmingly voted to approve a plan to merge with Deutsche Boerse, said on Monday the companies were evaluating the potential lowering of the approval threshold for the German Exchange's investors.

Deutsche Boerse said it was concerned that the 75 per cent threshold for its shareholders to approve the deal might prove difficult to cross because index funds which hold up to 15 per cent of its shares are unable to accept the offer until the minimum level of acceptances has already been reached.

The companies said in separate statements that the parties involved were looking at the potential for lowering the minimum acceptance threshold “with a view to enabling index funds to participate in the offer”.

A final decision on whether to lower the minimum threshold will be made on Monday, they said.

LSE said on Thursday that US and Russian authorities had approved the merger, giving it the first set of regulatory clearances needed to create a European exchange giant.

Reuters