Last year set a record for mergers and acquisitions worldwide: Deals totaled $3.79 trillion—or 38% higher than in 2005, and 55 of the transactions were valued at more than $10 billion each, according to Thomson Financial data. Private equity firms were “major movers in this trend,” responsible for 20% of the global M&A activity and 27% of U.S. deals, says a new report by U. Penn.’s Wharton School of Business. But, “how long will this M&A binge continue, and when it does come to an end, what will be the factors behind the retreat?” For the answers from Wharton Management Professor Harbir Singh, click here.