From Margin of Safety:
It is not clear why investors suddenly came to accept EBITDA as a measure of corporate cash flow. EBIT did not accurately measure the cash flow from a company’s ongoing income stream. Adding back 100% of depreciation and amortization to arrive at EBITDA rendered it even less meaningful. Those who used EBITDA as a cash-flow proxy, for example, either ignored capital expenditures or assumed that businesses would not make any, perhaps believing that plant and equipment do not wear out. In fact, many leveraged takeovers of the 1980s forecast steadily rising cash flows resulting partly from anticipated sharp reductions in capital expenditures. Yet the reality is that if adequate capital expenditures are not made, a corporation is extremely unlikely to enjoy a steadily increasing cash flow and will instead almost certainly face declining results.
It is not easy to determine the required level of capital expenditures for a given business. Businesses invest in physical plant and equipment for many reasons: to remain in business, to compete, to grow, and to diversify. Expenditures to stay in business and to compete are absolutely necessary. Capital expenditures required for growth are important but not usually essential, while expenditures made for diversification are often not necessary at all. Identifying the necessary expenditures requires intimate knowledge of a company, information typically available only to insiders. Since detailed capital-spending information was not readily available to investors, perhaps they simply chose to disregard it.
Some analysts and investors adopted the view that it was not necessary to subtract capital expenditures from EBITDA because all the capital expenditures of a business could be financed externally (through lease financing, equipment trusts, nonrecourse debt, etc.). One hundred percent of EBITDA would thus be free pretax cash flow available to service debt; no money would be required for reinvestment in the business. This view was flawed, of course. Leasehold improvements and parts of a machine are not typically financeable for any company. Companies experiencing financial distress, moreover, will have limited access to external financing for any purpose. An over-leveraged company that has spent its depreciation allowances on debt service may be unable to replace worn-out plant and equipment and eventually be forced into bankruptcy or liquidation.
EBITDA may have been used as a valuation tool because no other valuation method could have justified the high takeover prices prevalent at the time. This would be a clear case of circular reasoning. Without high-priced takeovers there were no upfront investment banking fees, no underwriting fees on new junk-bond issues, and no management fees on junk-bond portfolios. This would not be the first time on Wall Street that the means were adapted to justify an end. If a historically accepted investment yardstick proves to be overly restrictive, the path of least resistance is to invent a new standard.