The list of complications that arise when cross-border exchanges seek to merge is not a short one, and the merging parties have to run the table in having things go their way: if just one thing goes wrong, that can derail a deal.

“People will watch NYSE Euronext and Deutsche Borse closely, and wait for confirmation that European regulators will let it go through,” said Simmy Grewal, equity markets analyst at Aite Group. As the new group would create a massive entity, one that spans a substantial portion of Europe, there are sure to be monopolistic concerns, especially with regard to derivatives.

If the NYSE Euronext-Deutsche Borse merger does go through, it would step up pressure on competing exchanges to keep up in the race to build size and scale.

“The competitive landscape would change. It would be the most global, the most diversified, and the strongest voice in regulatory hearings,” said Michael Wong of Morningstar. “Going forward, NYSE Euronext-Deutsche Borse may be the prime consolidator in every single asset class, with its strong operations in Europe and the U.S.”

“NYSE Euronext-Deutsche Borse would put a lot of pressure on other exchanges to think about some sort of merger, since that would create such a strong entity,” Grewal said. “It would be huge in the exchange space. It would leave others like the LSE to think they have to do something,” as it would with some Asian exchanges.

If Deutsche Borse proceeds to buy NYSE Euronext, “it should be very encouraging for other exchanges that are looking to merge,” said Wong. “I don’t think this current wave of exchange mergers is over with yet.”

But if the merger hits a snag, that may be the third strike. “If it fizzles out, that will stop the M&A activity,” Grewal said. “Other exchanges will give up.”