European stock market Euronext has met with the London Stock Exchange (LSE) amid speculation that it may be ready to launch a cash bid.
The rival suitors put their cases to the LSE this week
Euronext chief Jean-Francois Theodore held talks with LSE boss Clara Furse the day after rival Deutsche Boerse put forward its own bid case.
The German exchange said it had held "constructive, professional and friendly" talks with the LSE.
But Euronext declined to comment after the talks ended on Friday.
Speculation is mounting that the Germans may raise their bid to £1.5bn.
Deutsche Boerse previously offered £1.3bn, which was rejected by the LSE, while Euronext is rumoured to have facilities in place to fund a £1.4bn cash bid.
So far, however, neither have tabled a formal bid.
But a deal with either bidder would create the biggest stock market operator in Europe and the second biggest in the world after the New York Stock Exchange.
German job losses?
There was speculation Euronext would use Friday's meeting as an opportunity to take advantage of growing disquiet over Deutsche Boerse's own plans for dominance over the London market.
Unions for Deutsche Boerse staff in Frankfurt has reportedly expressed fears that up to 300 jobs would be moved to London if the takeover is successful.
"The works council has expressed concerns that the equities
and derivatives trade could be managed from London in the future," Reuters news agency reports a union source as saying.
German politicians are also said to be angry over the market operator's promise to move its headquarters to London if a bid were successful.
Meanwhile, LSE shareholders fear that Deutsche Boerse's control over its Clearstream unit - the clearing house that processes securities transactions - would create a monopoly situation.
This would weaken the position of shareholders when negotiating lower transaction fees for share dealings.
LSE and Euronext do not have control over their clearing and settlement operations, a situation which critics say is more transparent and competitive.
The German group's ownership of Clearstream has been seen as the main stumbling block to a London-Frankfurt merger.
Commentators believe Deutsche Boerse, which has now formally
asked German authorities to approve its plan to buy
the LSE, may offer to sell Clearstream to gain shareholder approval.
Euronext, so far, has given little away as to what sweeteners it will offer the LSE - Europe's biggest equity market - into a deal.