From Caterpillar to Chevron to Google, some of the best-known names in corporate America are scooping up smaller companies, finally putting the piles of cash they've been sitting on to use and positioning themselves for a stronger economic recovery.

The volume of mergers and acquisitions is still running well below what it was in 2007 before the Great Recession, but the burst in activity is a sign of economic vitality and shows that companies are starting to shake off some of their caution.

"Our pipeline is bursting," says Robert Profusek, head of mergers and acquisitions at the law firm Jones Day, who advised Continental Airlines when it was acquired by the parent of United for $3.2 billion. "We are gearing up for an incredible M&A boom."

M&A volume reached $2.25 trillion in the first 10 months of the year, a 28 percent increase over last year. August was the highest month on record, with $307 billion in deals, more than double August 2009, according to Dealogic, which tracks such data. October remained strong with $202 billion deals, up 32 percent from last year.