"The M&A activity is, in a sense, a lagging indicator," said Parr, whose firm has advised on some of the biggest recent mergers including AT&T 's $49 billion buy of DirecTV.
Since the depths of the 2008 financial crisis, he said, "Finally we're at a place where boards and managements are comfortable again, confident again about taking the risks of mergers."
"The stock market is [also] still rewarding mergers, by and large, even for the buyers," he told CNBC's " Squawk Box " in an interview. "[But] the one aspect of merger activity is companies should be taking a longer-term view. It's not like a stock trade."
Citing data from Dealogic, The Wall Street Journal reported Monday that M&A activity could reach $4.58 trillion this year, which would exceed the record levels of 2007, if the current pace of deals were to continue.
M&A volume has already reached $3 trillion in 2015, the second fastest to that mark behind 2007 when it was reached in late July.
Just this week, Warren Buffett 's Berkshire Hathaway announced plans to acquire aircraft equipment maker Precision Castparts in deal valued at $32.3 billion.
Norton antivirus software maker Symantec also agreed to sell its data storage unit, Veritas, for $8 billion to a group led by Carlyle Group .
Health care leads all sectors with deals worth $482.3 billion in 2015, including Anthem' s late July agreement to buy Cigna for $47 billion. which came just weeks after Aetna 's $37 billion deal to buy Humana .
Even with those staggering numbers, Parr said, "If you look at ... the dollar volume, for example, relative to the stock market, we're just approaching sort of a historic mean. We're not at a bubble place."
Parr does not see China's currency devaluation or a Federal Reserve interest rate hike putting the brakes on the pace of deals. Though he did say mergers could slow down if the stock market were to experience a sustained selloff from either of those factors or if the price of oil "really plummets."
The Fed is expected to raise rates for the first time in nine years at either its September or December meeting. Bets on next month's gathering seemed to come back into favor after last Friday's solid July employment report. But with the Chinese yuan moving lower for a third straight day Thursday, expectations appear to be tilting for an initial Fed move in December.