Intercontinental Exchange has confirmed that it is considering making an offer for the London Stock Exchange, following the announcement last week of merger talks between the LSE and Deutsche Bourse.
ICE has until 29 March to submit a counterbid and has hired Morgan Stanley to advise it on a deal.
In a statement, ICE says: "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. There can be no certainty that any offer will be made, nor as to the terms on which any offer will be made."
ICE is no stranger to M&A, having grown its business spectacularly through the takeover of the New York Stock Exchange and its recent $5.2 billion acquisition of Interactive Data Corp.
Other suitors are also circling, with the CME rumoured to be preparing a pitch.
The news sent LSE's shares to a record high, rising by almost eight percent in morning trading.