Valuation Metrics: How to Know If a Stock Is Cheap or Expensive
Price tells you what you pay. Value tells you what you get. Learning to distinguish between the two is the most important skill in investing.
Valuation Metrics: How to Know If a Stock Is Cheap or Expensive
Price tells you what you pay. Value tells you what you get. Learning to distinguish between the two is the most important skill in investing.
Price vs. Value
Every day, millions of investors buy and sell stocks based on price alone — chasing momentum, following tips, reacting to headlines. But price without context is meaningless. A $500 stock can be cheap if the underlying business generates enormous earnings. A $5 stock can be expensive if the company is burning cash and heading toward bankruptcy.
Valuation metrics provide the context. They translate a company's financial performance into ratios that allow you to compare, assess, and make informed decisions about whether a stock's price is justified by its fundamentals.
The Essential Metrics
| Metric | Formula | What It Tells You | Good Range* | Limitation |
|---|---|---|---|---|
| P/E Ratio | Price / Earnings per Share | How much you pay per $1 of earnings | 10–25x (varies by sector) | Ignores growth, debt, cash flow |
| PEG Ratio | P/E / Earnings Growth Rate | P/E adjusted for growth | < 1.0 = undervalued | Depends on growth estimate accuracy |
| P/B Ratio | Price / Book Value per Share | Price relative to net assets | < 1.5 (value), > 3.0 (growth) | Intangible assets not captured |
| P/S Ratio | Price / Revenue per Share | Useful for unprofitable companies | < 2.0 (mature), < 10 (high growth) | Ignores profitability entirely |
| EV/EBITDA | Enterprise Value / EBITDA | Accounts for debt in valuation | 8–15x (varies by sector) | Ignores capex, taxes |
| FCF Yield | Free Cash Flow / Market Cap | Cash generation relative to price | > 5% attractive | Cyclical businesses can mislead |
| Dividend Yield | Annual Dividend / Price | Income return on investment | 2–5% (sustainable) | High yield may signal distress |
*Ranges are rough guidelines only. Every metric must be evaluated in the context of the company's industry, growth rate, competitive position, and economic environment.
P/E Ratio: The King of Metrics
The Price-to-Earnings ratio is the most widely used valuation metric. It answers a simple question: how many years of current earnings would it take to pay back the stock's price? A P/E of 20 means you're paying $20 for every $1 of annual earnings — or equivalently, a 5% earnings yield.
The S&P 500's long-term average P/E is approximately 16. When the market trades significantly above this level (as it has for much of the past decade), it suggests that investors are pricing in strong future growth — or that the market is overvalued. When it trades below, it often signals fear and opportunity.
| S&P 500 P/E Level | Market Interpretation | Historical Context |
|---|---|---|
| < 12 | Deep value / fear | 2008-09 financial crisis, 1980-82 |
| 12–16 | Fair value / neutral | Long-term average range |
| 16–22 | Moderately elevated | Most of 2010s-2020s |
| 22–30 | Expensive / euphoria | Late 1990s, 2020-21 |
| > 30 | Extreme overvaluation | 1999-2000 dot-com peak |
The Shiller CAPE Ratio
Nobel laureate Robert Shiller developed the Cyclically Adjusted Price-to-Earnings (CAPE) ratio to smooth out earnings volatility. Instead of using a single year of earnings, CAPE uses the average of inflation-adjusted earnings over the past 10 years. This makes it more reliable for assessing long-term market valuation.
The historical average CAPE for the S&P 500 is approximately 17. As of early 2026, it stands significantly above this level — suggesting that future long-term returns from US equities may be lower than historical averages, though elevated CAPE ratios have persisted for extended periods in recent decades.
Beyond Stocks: Valuing Other Assets
| Asset Class | Key Valuation Metrics | What to Watch |
|---|---|---|
| Bonds | Yield, Duration, Credit Spread | Higher yield = higher risk; watch spreads vs Treasuries |
| Real Estate | Cap Rate, Price/Rent, Price/Income | Compare to local rent yields and historical averages |
| Bitcoin | Stock-to-Flow, MVRV, NVT Ratio | On-chain metrics unique to crypto — covered in Art. 3 |
| Gold | Gold/CPI Ratio, Real Rates | Gold rises when real interest rates are negative |
| ETFs / Index | Weighted average P/E, P/B of holdings | Check what you actually own inside the wrapper |
Putting It All Together
Valuation is not about finding the "right" number — it's about building a framework for disciplined decision-making. Before buying any asset, ask yourself: what am I paying, and what am I getting in return? If the price assumes perfection, the risk is high. If the price assumes disaster, the opportunity may be extraordinary.
This week we've covered compound interest, asset allocation, risk management, and now valuation. Together, these four pillars form the foundation of rational investing. Master them, and you'll be better equipped than 90% of market participants.
Metriche di Valutazione: Come Sapere Se un'Azione è Cara o a Buon Mercato
Il prezzo vi dice cosa pagate. Il valore vi dice cosa ottenete. Imparare a distinguere tra i due è la competenza più importante nell'investimento.
Prezzo vs. Valore
Ogni giorno, milioni di investitori comprano e vendono azioni basandosi solo sul prezzo. Ma il prezzo senza contesto non ha significato. Un'azione da €500 può essere a buon mercato se l'azienda genera utili enormi. Un'azione da €5 può essere cara se l'azienda brucia cassa e si dirige verso la bancarotta.
Le metriche di valutazione forniscono il contesto. Traducono la performance finanziaria in rapporti che permettono di confrontare, valutare e prendere decisioni informate.
Le Metriche Essenziali
| Metrica | Formula | Cosa Vi Dice | Range Indicativo |
|---|---|---|---|
| P/E | Prezzo / Utile per Azione | Quanto pagate per €1 di utili | 10–25x |
| PEG | P/E / Tasso Crescita Utili | P/E aggiustato per la crescita | < 1,0 = sottovalutato |
| P/B | Prezzo / Valore Contabile | Prezzo rispetto al patrimonio netto | < 1,5 (value) |
| P/S | Prezzo / Ricavi | Utile per aziende non profittevoli | < 2,0 (mature) |
| EV/EBITDA | Enterprise Value / EBITDA | Tiene conto del debito | 8–15x |
| FCF Yield | Free Cash Flow / Cap. di Mercato | Generazione di cassa | > 5% attraente |
| Dividend Yield | Dividendo Annuo / Prezzo | Rendimento da reddito | 2–5% |
Il Rapporto P/E: Il Re delle Metriche
Il P/E medio storico dell'S&P 500 è circa 16. Quando il mercato tratta significativamente sopra questo livello, suggerisce che gli investitori prezzano una forte crescita futura — o che il mercato è sopravvalutato.
| P/E S&P 500 | Interpretazione | Contesto Storico |
|---|---|---|
| < 12 | Valore profondo / paura | Crisi 2008-09 |
| 12–16 | Valore equo | Media storica |
| 16–22 | Moderatamente elevato | 2010s-2020s |
| 22–30 | Costoso / euforia | Fine anni '90, 2020-21 |
| > 30 | Sopravvalutazione estrema | Bolla dot-com 1999-2000 |
Il CAPE di Shiller
Il premio Nobel Robert Shiller ha sviluppato il CAPE per smussare la volatilità degli utili, usando la media degli ultimi 10 anni aggiustata per l'inflazione. La media storica è circa 17.
Mettere Tutto Insieme
Questa settimana abbiamo coperto interesse composto, asset allocation, gestione del rischio e ora valutazione. Insieme, questi quattro pilastri formano le fondamenta dell'investimento razionale.
Métriques de Valorisation : Comment Savoir Si une Action Est Chère ou Bon Marché
Le prix vous dit ce que vous payez. La valeur vous dit ce que vous obtenez. Apprendre à distinguer les deux est la compétence la plus importante en investissement.
Prix vs. Valeur
Chaque jour, des millions d'investisseurs achètent et vendent des actions en se basant uniquement sur le prix. Mais le prix sans contexte n'a pas de sens. Une action à 500 € peut être bon marché si l'entreprise génère des bénéfices énormes. Une action à 5 € peut être chère si l'entreprise brûle du cash.
Les Métriques Essentielles
| Métrique | Formule | Ce Qu'Elle Vous Dit | Fourchette |
|---|---|---|---|
| P/E | Prix / Bénéfice par Action | Combien vous payez par 1 € de bénéfice | 10–25x |
| PEG | P/E / Taux de Croissance | P/E ajusté pour la croissance | < 1,0 |
| P/B | Prix / Valeur Comptable | Prix relatif aux actifs nets | < 1,5 (value) |
| P/S | Prix / Chiffre d'Affaires | Utile pour les entreprises non rentables | < 2,0 |
| EV/EBITDA | Valeur d'Entreprise / EBITDA | Tient compte de la dette | 8–15x |
| FCF Yield | Cash Flow Libre / Cap. Boursière | Génération de trésorerie | > 5 % |
| Rendement Dividende | Dividende Annuel / Prix | Rendement en revenu | 2–5 % |
Le Ratio P/E : Le Roi des Métriques
Le P/E moyen historique du S&P 500 est d'environ 16. Quand le marché se négocie significativement au-dessus, cela suggère que les investisseurs intègrent une forte croissance future — ou que le marché est surévalué.
Le CAPE de Shiller
Le CAPE utilise la moyenne des bénéfices ajustés à l'inflation sur 10 ans. La moyenne historique est d'environ 17.
Au-delà des Actions
| Classe d'Actif | Métriques Clés | À Surveiller |
|---|---|---|
| Obligations | Rendement, Duration, Spread | Rendement élevé = risque élevé |
| Immobilier | Taux de Capitalisation, Prix/Loyer | Comparer aux rendements locatifs |
| Bitcoin | Stock-to-Flow, MVRV, NVT | Métriques on-chain uniques |
| Or | Or/IPC, Taux Réels | L'or monte quand les taux réels sont négatifs |
| ETFs | P/E moyen pondéré des composants | Vérifier le contenu réel |
Tout Assembler
Cette semaine nous avons couvert les intérêts composés, l'allocation d'actifs, la gestion du risque et maintenant la valorisation. Ensemble, ces quatre piliers forment les fondations de l'investissement rationnel.