ABN Amro and existing advisers on the ICE/NYSE deal, Societe Generale and JP Morgan, will act as global coordinators on the flotation of the combined Paris, Lisbon, Brussels and Amsterdam exchanges, the sources said.

ICE decided to float Euronext when it sealed a deal with NYSE Euronext last year in order to fund the transaction, to ease regulatory approval in Europe and to keep the combined group's focus on U.S. operations, one of the people said. ICE will however keep NYSE's Liffe interest rate futures exchange.

The U.S.-based exchange operator is planning to float about 50 percent of Euronext in Paris in the second quarter of next year and will retain about 30 percent, one of the sources said.

Euronext is worth about 1.5 billion euros ($2.01 billion) and a partial listing could help ICE-NYSE raise about 750 million euros ($1 billion), said the same person, who added a secondary listing in Amsterdam was also being reviewed.

While an initial public listing (IPO) remains the most likely route, Euronext may also combine part or all of its activities with European rivals such as Germany's Deutsche Boerse or the Russian, Polish or Austrian stock exchanges, two of the people said.

"ICE and NYSE will listen to propositions," said one source, who asked not to be named because the talks are private.

Another of the three sources said that the IPO could be "pre-empted with a good offer".

"They've had a few discussions with possible buyers so far," he said.

OPEN GAME

Bankers expect further sector consolidation in the coming months as exchanges try to boost revenue by diversifying products and buying into settlement and clearing operations.

"It's very clear that sector consolidation is not over yet. Europe is pretty busy at the moment but you could see intra-consolidation in Eastern Europe, Asia and cross-border deals to combine geographies too," the third source said.

"The game is pretty open," he said.

Deutsche Boerse may try to buy into Euronext's cash equities operation to diversify from its core derivatives business, two of the sources said, although another source close to the German exchange told Reuters that this was not an area where it was looking for acquisitions.

U.S. rival Nasdaq and London's LSE are also among the interested parties, all three sources said, although the EU's regulator may block a non-European sale, one said.

Deutsche Boerse is under the most pressure to act and, while a tie-up with its larger peer in Hong Kong would mean selling out, it could buy the Singapore stock exchange, he said, although it would be hard to create synergies across continents.

Deutsche Boerse's diversification strategy centres on expanding post-trade services such as clearing, the same source said.

Asian stock exchanges such as Singapore, Seoul or Hong Kong could also be targets for Nasdaq or the Tokyo and Shanghai exchanges, a separate source said.

Nasdaq is also looking to expand in the Middle East and may be interested in operators such as Dubai stock exchange, the same person said.

Euronext, JPMorgan, Deutsche Boerse all declined to comment, while other parties were not immediately available for comment. ($1 = 0.7476 euros)

(Additional reporting by Christian Plumb, Alexandre Bokenbaum-Granier in Paris and Ed Taylor in Frankfurt; Editing by Louise Ireland and David Evans)

By Sophie Sassard and Anjuli Davies