There are two key factors playing a role in the slowdown, says Steve Krouskos, a partner at Ernst & Young whose department advises buyers and sellers on mergers and acquisitions. One is that companies have been shedding parts of their businesses that aren't core to organic growth. That means the days of growth by acquisition appear to be over--at least for the time being. Second, many of the most common, low-profile deals in sectors such as industrial products, real estate, and financial services have dropped off.
But the silent killer in the M&A world is uncertainty. In addition to continuing worries about Europe and daily fights between the U.S. presidential candidates about the future of tax policy, executives are most concerned about what's happening in China, says Thomas Herd of Accenture; he consults with buyers and sellers on mergers and acquisitions.

Where Have All the M&A Deals Gone?