$388.5 billion is a staggering figure. It's more than the entire economy of Thailand, Denmark, Colombia or the United Arab Emirates.
And it's how much operating cash flow was generated by America's top 12 companies in 2012.


Source: Thomson Reuters

Of course, the old adage "It takes money to make money" applies. Many of these companies need to spend billions of dollars in research, infrastructure and other areas to generate that cash flow, and their actual take-home pay is a lot less. Exxon Mobil (NYSE: XOM), for example, spent more than $34 billion on capital expenditures last year, sapping a considerable chunk of its $56 billion in operating cash flow.
As a bit of silver lining, these companies spend much of that on goods and services offered by other companies, creating a virtuous circle of corporate spending. Here are the top 12 capex spenders of 2013.


Source: Thomson Reuters

The number of oil and gas firms in this group explains why an energy services provider like Schlumberger (NYSE: SLB) sports a $120 billion market value, but is not truly a household name.

The True Measure
Unfortunately, even as many Wall Street analysts wisely avoid a simple focus on net profits, their decision to value stocks in the context of operating cash flow is also mistaken. It's irrelevant that Exxon Mobil generated $56 billion in 2012 free cash flow. After capital expenditures are deducted, free cash flow falls by more than half to $22 billion. It's still an impressive figure, but knocks the oil giant from the leaderboard.

Rather than focus on operating cash flow, check out a company's free cash flow, which is the only bankable source of stock buybacks, dividends, acquisitions and debt pay downs. Indeed some of the top-performing stocks in today's market share some of all of those characteristics. Here's a look at the top 12 companies in America in terms of free cash flow.