The fate of some of the biggest takeover deals in recent weeks will ultimately rest in the hands of antitrust regulators, an antitrust attorney told CNBC Monday.
"This is the moment of truth for antitrust," said Stephen Axinn, senior partner at Axinn, Veltrop & Harkrider, a law firm specializing in antitrust and trade regulation.
Among the big deals likely to face antirust scrutiny: AT&T's $39 billion agreement to purchase Deutsche Telekom's T-Mobile USA and the joint proposal by Nasdaq Omx and Intercontinental Exchange' to acquire NYSE Euronext, a 19 percent premium over the proposed Deutsche Boerse takeover bid.
"When you have that sort of activity taking place that puts great pressure on the leaders of antitrust regulatory agencies," Axinn said.
Under the Clayton Act[an amendment passed in 1914 to prohibit certain actions that lead to anti-competitiveness] the antitrust division is required to examine the effect of any merger or other transaction on commerce in the United States, he explained.
"The anti-trust laws are there to protect the process of competition, not individual competitors," Axinn went on to say.
In addition, he thinks a potential NYSE merger with Nasdaq is very troublesome because there are several markets that would be implicated as a result.
"They have 100 percent of the listings market in the United States, there's the equity options market, as well, and the simple trading of equity securities for domestic United States investors—in all three of those cases the market shares are very high."
"To some extent this [M&A activity] is all a part of what I think is a secular reawakening of M&A activity in this country after a long quiet period—the end of the Bush administration and the beginning of the Obama administration," Axinn concluded.
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