LONDON/FRANKFURT (Reuters) - IntercontinentalExchange (>> IntercontinentalExchange Inc) would consider selling Euronext as an alternative to floating it if bids for the European stock market emerge during ICE's planned $8.2 billion takeover of NYSE Euronext, three sources close to the exchange said.

"Today, the plan is work on an IPO. But, of course, if some parties offered to acquire all or part of Euronext, then why not? We'll be pragmatic," a source familiar with ICE's plans said on Thursday.

ICE said last month it planned to float Euronext after it completes its acquisition of NYSE Euronext in the second half of this year. But the sources said ICE would also consider a sale, which could be easier to complete than an initial public offering (IPO) and could fetch a higher price.

One potential bidder has already indicated an interest in Euronext, which analysts have said could be worth between 1 and 2 billion euros, based on comparative market valuations.

Nasdaq OMX (>> NASDAQ OMX Group, Inc.) Chief Executive Robert Greifeld told Reuters on Wednesday he would "take a look" at Euronext if it became available.

A source close to the London Stock Exchange (>> London Stock Exchange Group Plc) did not rule out making an offer, but said it was "early days" and played down the chances of a bid, since the LSE's current priorities were derivatives and clearing rather than stock trading.

Deutsche Boerse (>> Deutsche Boerse AG), the Frankfurt-based group that failed to merge with NYSE Euronext last year, has ruled itself out of buying Euronext due to the weakness of the European share trading business, three people familiar with the company told Reuters.

The official line remains that Euronext is not on the block. NYSE Euronext deputy chief executive Dominique Cerruti told Reuters on Wednesday: "Euronext is not for sale", and a spokeswoman for ICE declined to comment on the possibility.

However, the future of Euronext, which operates the Paris, Amsterdam, Brussels and Lisbon stock exchanges, has been in doubt since ICE said late last month it planned to spin off Europe's third largest exchange after its purchase of NYSE Euronext.

Jeff Sprecher, the chief executive of ICE, said an IPO would establish the true value of Euronext, which has not been realized by NYSE Euronext's largely U.S. shareholders.

The first source said the size and structure of an IPO had yet to be decided, but the plan was for the listing to take place in Paris and it would not happen before 2014.

Euronext has a European market share of 16 percent, which equated to 76 trillion euros ($99 trillion) of trading last month, making it the third-ranking European exchange after the LSE (24.8 percent) and London-based Bats Chi-X Europe (22.3 percent), Thomson Reuters data shows.

LSE, Nasdaq OMX, NYSE Euronext and Deutsche Boerse have in recent years moved away from European share trading by diversifying into higher margin areas such as derivatives and clearing.

"Cash equities trading is a commoditizing business, but it seems a chunk of what ICE might spin out is derivatives, and that could be more interesting," said Richard Perrott of Berenberg Bank.

Nasdaq OMX plans to launch this year a new European futures exchange, while the British exchange hopes to complete its 366 million euro purchase of Anglo-French clearing house LCH.Clearnet before the end of March.

LCH.Clearnet, which was created after Clearnet was split from Euronext in 2003, acts as the clearing house to both the LSE and Euronext, so there are close ties between the three firms.

"Euronext could dovetail nicely with LSE and LCH.Clearnet. Clearnet used to be part of Euronext and remains the major clearing house for these continental markets," said Perrott.

ICE is buying NYSE Euronext for its London-based futures market Liffe, which is well positioned to tap the expected growth in futures trading as regulators force firms to start using exchanges for complex derivatives.

The Atlanta-based energy market said last month it wanted to keep the New York Stock Exchange, an enduring symbol of American capitalism, and float Euronext, most likely in 2014.

(Writing by Luke Jeffs; Additional reporting by Ed Taylor in Frankfurt, Blaise Robinson in Paris and John McCrank in New York; Editing by Alex Smith and Will Waterman)

By Sophie Sassard and Andreas Kröner