The U.S. exchanges left out of this week's flurry of announced acquisitions now need to consider whether they, too, should strike a deal, a Chicago Board Options Exchange executive said on Friday.

On Wednesday, powerhouse exchange operators Deutsche Boerse and NYSE Euronext said they were in advanced talks to merge, just hours after London Stock Exchange unveiled a bid for Canadian market operator TMX Group Inc.

Every exchange that wasn't involved in the two mergers -- the four that were not involved -- had to at lunch on Wednesday be asking themselves, 'Should I be involved in some way?' and calling their bankers and thinking strategically, said Alan Dean, chief financial officer of CBOE Holdings Inc.

It has to be a jolt I think for all market participants in this industry, he said at a conference hosted by Credit Suisse.

CBOE, the largest of the U.S. options venues, is seen as a likely takeover target.

At the same conference, CBOE Executive Vice Chairman Edward Tilly said he expected to compete with three separate exchanges -- ISE, Amex, and Arca -- if NYSE Euronext is taken over as planned, putting the three venues under one roof.

We think we're going to be competing with the same three exchanges, perhaps just managed with one global overview, Tilly said.

(Reporting by Jonathan Spicer; Editing by Lisa Von Ahn and Matthew Lewis)