This article offers investment advice and warns against making an investment choice based on a company's free cash flow. What makes Jack In The Box, a chain of 2,200 hamburger and Mexican fast-food restaurants, worth $1.3 billion on Wall Street? Perhaps investors are awed by the company's ability to grow even as it's putting its capital costs on a diet. Jack's free cash flow, or cash from operations minus capital expenditures, climbed from $34 million to $90 million. Free cash flow is much in vogue on Wall Street these days. But Jack in the Box doesn't subtract from its free cash flow $10 million that it had spent on restaurant buildings and equipment. Doing so would lower its free cash flow to $80 million, says Charles Mulford, an accounting expert who runs the Georgia Tech Financial Analysis Lab. Instead the costs of the leases are being financed with a "capital lease," a perfectly legit accounting move which delivers all the effects of a heavily mortgaged asset but keeps the asset's cost out of the free cash flow calculation. "Free cash flow is always inflated when capital leases are used, because companies don't have to subtract these very real costs of doing business as cap-ex and instead can bury them in the financials," says Mulford. That makes the stock look cheaper than it really is. Capitalized leases don't affect earnings. Rather they boost free cash flow. Investors who want an accurate free cash flow number have to create it themselves by reading the footnotes.