The Education of Warren Buffett 21cash it will earn over its lifetime and then discount that total back to a
present value. It is the underlying methodology that Warren Buffett
uses to evaluate stocks and companies.
Buffett condensed Williams’s theory as: “The value of a business is
determined by the net cash f lows expected to occur over the life of the
business discounted at an appropriate interest rate.” Williams described
it this way: “A cow for her milk; a hen for her eggs; and a stock, by
heck, for her dividends.”^11
Williams’s model is a two-step process. First it measures cash f lows
to determine a company’s current and future worth. How to estimate
cash f lows? One quick measure is dividends paid to shareholders. For
companies that do not distribute dividends, Williams believed that in
theory all retained earnings should eventually turn into dividends.
Once a company reaches its mature stage, it would not need to reinvest
its earnings for growth so the management could start distributing the
earnings in the form of dividends. Williams wrote, “If earnings not
paid out in dividends are all successfully reinvested, then these earnings
should produce dividends later; if not, then they are money lost. In
short, a stock is worth only what you can get out of it.”^12
The second step is to discount those estimated cash f lows, to allow
for some uncertainty. We can never be exactly sure what a company will
do, how its products will sell, or what management will do or not do to
improve the business. There is always an element of risk, particularly for
stocks, even though Williams’s theory applies equally well to bonds.
What, then, should we use as a discount rate? Williams himself is
not explicit on this point, apparently believing his readers could deter-
mine for themselves what would be appropriate. Buffett’s measuring
stick is very straightforward: He uses either the interest rate for long-
term (meaning ten-year) U.S. bonds, or when interest rates are very low,
he uses the average cumulative rate of return of the overall stock market.
By using what amounts to a risk-free rate, Buffett has modif ied
Williams’s original thesis. Because he limits his purchases to those with
Ben Graham’s margin of safety, Buffett ensures that the risk is covered
in the transaction itself, and therefore he believes that using a risk-free
rate for discounting is appropriate.
Peter Bernstein, in his book Capital Ideas,writes that Graham’s
system is a set of rules, whereas Williams’s dividend discount model is a