Monday's deal news was all in the health-care industry. Mars Petcare announced it would acquire pet hospital operator VCA for $9.1 billion, Japan's Takeda said it would buy Massachusetts-based Ariad Pharmaceuticals for $5.2 billion and UnitedHealth's Optum unit announced it would purchase Surgical Care Affiliates for $3.97 billion, according to S&P.
"We're off to a good start, better than we were last year. ... Investors should have some confidence in the flow of deal activity," Peterson said. Increased corporate deal activity is generally seen as a positive sign for market health.
The strong start to corporate deal announcements in 2017 coincides with a 1.34 percent gain for the S&P 500 so far this year. In 2016, the S&P had its worst five-day start to a year in history, according to Howard Silverblatt, senior index analyst at S&P Dow Jones Indices.
Stocks and dealmaking activity had recovered significantly by the end of 2016. The S&P 500 gained 9.5 percent.
Last year also saw $1.7 trillion in announced U.S. corporate deals, the third biggest year ever by value, according to S&P. October 2016 marked a record month for such mergers and acquisitions, including an $85 billion-plus agreement between AT&T and Time Warner.
Analysts then generally attributed the surge in corporate deals to the rise in interest rates, as companies tried to lock in lower financing costs ahead of further increases in borrowing costs.