The big idea behind serious valuation: a company’s intrinsic value is the value today of all the cash it will generate in the future (discounted back to now — the intuition behind a discounted cash-flow, or DCF, model). Buying comfortably below that value is Benjamin Graham’s margin of safety.
A company’s true worth — its intrinsic value — is the value today of all the cash the business will hand its owners in the future. The economist John Burr Williams laid this out in 1938 (The Theory of Investment Value): a stock is worth the cash it will generate over its life, no more and no less. Everything else — P/E, margins, growth — is a shortcut for estimating that.
You can’t just add up future cash, because money in the future is worth less than money today: today’s dollar can be invested and grow, and future money is also less certain. So future cash is discounted — shrunk back to what it’s worth today — before you add it up. The rate you shrink it by is the discount rate, and the whole exercise is a discounted cash-flow (DCF) valuation, applied to the free cash flow a business actually generates.
Example (illustrative): a business will hand you $110 in cash one year from now, and you decide money a year out is worth 10% less to you today (a discount rate of 10%). Then that future $110 is worth $110 ÷ 1.10 = $100 to you now. Pay $105 and you’re overpaying; pay $90 and you’re getting a bargain. A real DCF does this for many years of estimated cash and adds up the discounted amounts — but the core move is exactly this. Illustrative arithmetic, not a real company or a recommendation.
Once you have an estimate of intrinsic value, compare it with the market price. If value sits well above price, the stock may be undervalued; well below, overvalued. Benjamin Graham — Warren Buffett’s teacher, in The Intelligent Investor — called the gap the margin of safety: only buy when the price is comfortably below your estimate of value, so a cushion protects you if your estimate is too optimistic. It exists precisely because valuation is uncertain.
A DCF looks precise but rests on estimates — future cash flows, growth, the discount rate — and small changes swing the answer a lot. It’s a tool for thinking clearly about value, not a machine that prints the “right” price. That’s why Graham insisted on a margin of safety, and why serious investors treat any single valuation number as a range.
Each of the three concepts in this lesson also has its own glossary page, linked below, going deeper than this lesson does: intrinsic value, discounted cash flow (with the full formula and a worked example) and margin of safety.
General investor education, not personalized advice. The discounting figures ($110 next year at a 10% discount rate ≈ $100 today) are illustrative arithmetic, not a real company or a recommendation. A DCF is only as good as its estimates: small changes in the inputs swing the answer a lot, so any valuation number is a range, not a certainty.
What a company is really worth based on the cash it will generate in the future, valued in today’s money — John Burr Williams’ idea that a stock is worth the discounted sum of its future cash flows.
Because a dollar in the future is worth less than a dollar today: today’s dollar can be invested and grow, and future money is less certain. Discounting shrinks each future amount back to its value now before you add them up. The rate you use is the discount rate.
Benjamin Graham’s rule of only buying when the market price is comfortably below your estimate of intrinsic value, so a cushion protects you if your estimate is too optimistic. It exists precisely because valuation is uncertain — a DCF is a tool for thinking, not a machine that prints the exact right price.
Investor education only — not investment advice, and never a promise of profit. Every investment can lose value.