An NYSE Euronext (NYX.N) merger with Nasdaq OMX (NDAQ.O) makes little strategic sense whether the Big Board were the buyer or the seller, and antitrust regulators would likely block it, according to a source close to NYSE. Bringing the top two U.S. stock exchanges together would face "insurmountable antitrust problems," the source said on Wednesday, suggesting NYSE's board could look beyond the premium Nasdaq has offered and reject Nasdaq's bid outright. The focus on monopolies shows just how tricky it will be for the world's top exchange operators to pull off a rash of planned tie-ups that would revamp capital markets in North America, Europe and Asia. Just this week, Australia moved to block a buyout of its bourse by Singapore Exchange.
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