In most industries, M&A is dominated by specific opportunities and needs, of course.

David McGirr, CFO of expects M&A in general to pick up a bit now that summer's over. "It's a bit like back to school," he says. "But I don't see any particular wall of pressure building up."

Cubist in the past has purchased companies to help fill its pharmaceutical pipeline, tends to be less affected by short-term market fears, according to McGirr. "If we look at buying a molecule that is going into Phase 3 trials in three or four years, the outlook is much longer," he says.

"We've bought a few companies that have interesting molecules," the most recent being Calixa, a San Diego-based company in the R&D stage, in December 2009. Cubist purchased that company to get a hold of CXA-201, an intravenous drug to be used to treat serious Gram-negative infections in hospitals. His company paid $92.5 million in cash up front for Calixa, agreeing to additional payments of up to $310 million as CXA-201 passes through regulatory hurdles and eventually starts to make money.