IntercontinentalExchange Inc CEO Jeffrey Sprecher and Nasdaq OMX Group CEO Robert Greifeld know what it is to try -- and fail -- to take over another exchange.

But their experiences may help them succeed if they go in together on a counter-bid for NYSE Euronext .

Four years ago, Sprecher launched an unsolicited bid for the Chicago Board of Trade, which had already agreed to a merger with the Chicago Mercantile Exchange. His offer to the CBOT board of directors ultimately failed.

There was a key shareholder whose decision probably decided where the company would end up, and we didn't pay enough attention to that shareholder, Sprecher told Reuters on the sidelines of the Futures Industry Association annual meeting in Boca Raton.

In 2007, CBOT shareholder Caledonia initially opposed CME's offer, but switched to support it after CME sweetened the bid and topped ICE.

When Sprecher made the first run at CBOT, I'm not sure he meant to do anything but make it more expensive for CME, said John Damgard, FIA president. He's a very smart business mind.

Sprecher -- who built ICE largely on successful acquisitions -- is now a critical part of Greifeld's possible plan to break up Deutsche Boerse AG's friendly takeover of the Big Board parent. A bid could come as early as this week, according to a source familiar with the situation.

It's unclear whether any bid would be pitched to the company itself, straight to shareholders, or will even come at all. Nasdaq's board was expected to meet Tuesday to discuss its options, a source said.

Greifeld bid for the London Stock Exchange in 2006, but was rebuffed by both management and shareholders. He later bought Scandinavian exchange operator OMX, and has since made several other smaller acquisitions.

Greifeld is a great integrator, and he seems to want to be a survivor, said Joe Gawronski, president of agency broker Rosenblatt Securities.

(Reporting by Ann Saphir and Jonathan Spicer, additional reporting by Paritosh Bansal in New York; Editing by Muralikumar Anantharaman)