Welcome to the Advanced course. From here on, the question changes. Beginner asked what am I buying? Intermediate asked how do I assemble a portfolio? This course asks the question that separates investing from collecting tickers: what is this business actually worth — and is the market asking more or less than that?
Start with the sentence everything else in this course hangs off. Price is what you pay; value is what you get. The price is on the screen, updated every second, and precise to the cent. The value is nowhere on the screen. It has to be estimated, it is never precise, and yet it is the only thing that makes a purchase sensible or foolish. A wonderful company at triple its worth is a bad investment. A mediocre company at half its worth can be a great one.
What you are actually valuing
A share is not a lottery ticket or a line on a chart. It is a claim on every dollar of cash this business will generate for its owners, from today until it stops. That is the whole game. Valuation is the act of guessing what those future dollars add up to, then translating them into today’s money.
Two things follow immediately from that definition. First, the future matters more than the present — a company earning little today but compounding fast can honestly be worth more than a giant earning plenty but shrinking. Second, a dollar later is worth less than a dollar now, because you could have invested the dollar now. The further away the cash and the shakier the promise, the harder you discount it. That single idea — discounting — is why interest rates move every asset on earth, and we will meet it again in Lesson 3.
Lens one: multiples
The quickest way to put a rough number on a business is to compare it to what similar businesses fetch. You already know the workhorse from the Intermediate course: the P/E ratio — the price of one dollar of current earnings. Analysts use cousins of it where P/E breaks down: price-to-sales for companies without profits yet, and EV/EBITDA when comparing companies with very different debt loads. Different numerators and denominators, same move: express the price as a multiple of something fundamental, then compare within the neighbourhood.
Multiples are fast, and that is both their strength and their trap. A multiple compresses every assumption about growth, risk and quality into a single number — and then hides them. Two companies at a P/E of 15 can deserve wildly different prices once you look at what is behind the 15.
Lens two: yield — the flip trick
Here is a habit worth stealing from professional investors: flip the P/E upside down. A P/E of 20 becomes an earnings yield of 5% (100 ÷ 20). A P/E of 50 becomes 2%. Suddenly a stock can be compared with anything else that pays: a bond yielding 4%, a savings account at 3%, another stock yielding 7%.
The comparison is not entirely fair — a bond’s coupon is contractual while earnings can grow or vanish — but that is exactly what makes it useful. When a stock’s earnings yield is below what a government bond pays, the market is telling you it expects serious growth. If you cannot articulate where that growth comes from, you are relying on someone else’s optimism.
Lens three: discounted cash flow — the honest machine
The formal version of “value equals future cash, discounted” is the DCF — discounted cash flow model. Project the company’s free cash flow year by year, shrink each year by a discount rate, add it all up. It is the intellectually correct way to value a business, and every serious valuation ultimately leans on its logic.
And yet you should treat every precise DCF output with suspicion, including your own. The model is honest; the inputs are guesses. Nudge the growth assumption from 8% to 10%, or the discount rate from 9% to 8%, and the “fair value” can jump by a third with nothing about the company having changed. A DCF does not tell you what a company is worth. It tells you what the company would be worth if your assumptions came true. Its real use is not the output number — it is forcing you to write your assumptions down where you can see how heroic they are.
Valuation is a range, and the gap is your seatbelt
Put the three lenses together and you never get one number — you get a range. Maybe the multiple says $60, the yield comparison says fair, and a sober DCF says $55–$80. Good. That range is the truth. Anyone quoting a company’s worth to the second decimal is decorating a guess.
Because the estimate is fuzzy, the price you pay has to do the protecting. That is the margin of safety: only buying when the price sits comfortably below the bottom of your estimated range, so that even if your assumptions were optimistic — and they usually are — you still paid a fair price. The margin of safety is not about maximising the win when you are right. It is about surviving being wrong, which over a long investing life you frequently will be.
One warning before the practice: a low price against your estimate of value is the beginning of a case, never the end of one. Some stocks trade far below any reasonable valuation because the market knows something the ratios have not caught up with yet. Telling the difference is the entire next lesson.