Jensen's Free Cash Flow Hypothesis

Free cash flow, in Michael Jensen's 1986 framing, is cash a company generates beyond what it needs to fund all its positive-NPV projects. The problem is what managers do with that surplus: rather than pay it out to shareholders as dividends or buybacks, managers often prefer to keep it inside the firm and spend it — on acquisitions, on expanding into new businesses, on pet projects — because a bigger company under their control typically means more prestige, more compensation, and more job security for them, even when the spending destroys shareholder value.

Jensen's proposed fix is debt. Committing the firm to regular interest and principal payments removes the discretionary cash before management can misallocate it: instead of a large pile of free cash flow sitting around waiting to be spent on a bad acquisition, the cash is contractually obligated to bondholders. This is why Jensen's hypothesis is often cited as a rationale for leveraged buyouts of mature, cash-generative businesses with few good reinvestment opportunities — loading the company with debt post-buyout forces exactly the payout discipline that equity-only ownership failed to provide.

Concrete illustration. A mature industrial company generates far more cash than its (limited) growth opportunities require, and its management has a history of using the surplus for diversifying acquisitions outside its core competence that have destroyed value. A private equity buyer takes it private with substantial leverage; the resulting debt service obligations leave no discretionary cash for empire-building acquisitions, and free cash flow instead goes toward paying down debt — precisely the mechanism Jensen described.