US-based global markets operator Intercontinental Exchange (ICE) said Tuesday it was mulling a bid for the London Stock Exchange Group, already in merger talks with Germany's Deutsche Boerse.
ICE, which owns the New York Stock Exchange, said in a statement that it was "considering making an offer for LSEG", which owns the London and Milan stock exchanges.
The US group said it would make a final decision on whether to bid for LSEG by March 29.
"No approach has been made to the board of LSEG, and no decision has yet been made as to whether to pursue such an offer," said ICE, which was created in 2000 and owns the London-based Liffe derivatives market.
In a brief response, LSEG noted the interest of ICE and confirmed no bid had been received.
Last week, the LSEG revealed it was in talks with Deutsche Boerse, which manages the Frankfurt stock exchange.
"Further to the announcement on 26 February 2016, discussions between LSEG and Deutsche Boerse AG regarding the potential merger of equals between the two groups continue to progress," the LSEG said on Tuesday.
Should the pair merge, an enlarged group would be based in London and headed by Deutsche Boerse chief executive Carsten Kengeter.
Deutsche Boerse shareholders would meanwhile end up with 54.4 percent of the new holding company's capital, and LSE shareholders with 45.6 percent.
Both the London and Frankfurt financial markets would continue doing business under their respective current brand names.
The tie-up plans constitute the third attempt at merging Europe's two biggest markets but it comes at a politically-sensitive time as Britain is due to hold a referendum on June 23 which would determine whether it remains in the EU.
Deutsche Boerse had previously sought to link up with NYSE Euronext, which operates the New York, Brussels, Amsterdam and Lisbon stock exchanges, but that move was blocked by the EU Commission in 2012 on competition grounds.