The Three Ratios That Matter Most for Smart Investing

When you're looking at a company's stock, the numbers can feel overwhelming. But here's the good news: you really only need to understand a few key ratios to make sound investment decisions. These ratios help you answer the most fundamental question — is this company worth my money compared to the alternatives?

Let's break down the three ratios that matter most, and how you can use them to evaluate any stock with confidence.

Earning Yield: Your Company's True Return

Let's start with what I believe is the most important ratio for any long-term investor — the earning yield.

The earning yield is simply the company's earnings divided by its price. So if a company earns $5 per share and its stock trades at $100, the earning yield is 5%. It's the inverse of the price-to-earnings multiple — when someone tells you a stock trades at 20 times earnings, the earning yield is exactly 1/20th, or 5%.

Now here's where things get interesting. You should always compare that earning yield to the current interest rate — specifically, what government bonds or treasury bills are paying you. That's your risk-free, guaranteed return.

Here's the logic: if a company's earning yield is 12% but government bonds are only paying you 8%, which is the better deal? All else being equal, you're better off buying that company than parking your money in government paper. The company is generating a higher return on your investment than the risk-free alternative.

The earning yield tells you what return the company is actually making for you. This makes it one of the most important ratios for anyone investing with a long-term horizon.

The Magic of Compounding When Yields Beat Interest Rates

Let's dig a little deeper into why the earning yield matters so much.

Say you find a company that consistently generates an earning yield of 12% year after year, while interest rates are sitting at 8%. That's a 4% gap in your favor, every single year. When you add in dividends and reinvest them, this is exactly how compounding works in the stock market.

The consistency part is critical. You want a company that reliably delivers this kind of return, not one that has one good year followed by several bad ones. A company that consistently earns more than the interest rate is one of the best assets you can hold in your portfolio for the long term — because you're compounding at a rate that beats the guaranteed alternative.

Dividend Yield: Getting Paid While You Wait

The second ratio to focus on is the dividend yield.

The dividend yield is the dividend a company pays out, divided by its stock price. Let's say a company pays a $4 dividend and trades at $100 — that's a 4% dividend yield.

Now, compare that to the interest rate again. If a bank or government bond is paying you 3% interest, but a company offers a 5% dividend yield, which is better?

You might think the government option is safer — after all, it's "guaranteed." But here's the key insight: the company has the ability to grow its earnings over time. It can reinvest in new machines, open new branches, hire more people, or expand its operations. The government bond just sits there paying you the same fixed rate. A thriving company can raise its dividends as profits grow.

So if a company in a stable sector like banking or fertilizer is consistently offering a dividend yield higher than the current interest rate, there's a strong chance it's a better place for your money. The dividend yield being higher than the interest rate is usually a very positive signal.

The Short-Term Investor Caveat

Now, I should note — this approach is primarily for the long-term investor. If you're a short-term trader, your focus shifts. Instead of comparing earning yield to interest rates, you're more concerned with inflation rates and immediate market movements. When inflation is running at 30% and the stock market is volatile, short-term decisions look very different from long-term ones.

But if you're building wealth over time, the earning yield and dividend yield comparison to interest rates is your compass.

Price-to-Book Value: The Safety Net

The third ratio to keep in your toolkit is the price-to-book value. This tells you what you're paying for the company relative to its net assets — what it actually owns after liabilities. It's a useful check on whether you're overpaying for a stock. When combined with the earning yield and dividend yield, it gives you a complete picture of a company's value.

Putting It All Together

So here's your simple framework:

• Earning yield (earnings ÷ price) tells you the company's actual return, and you should compare it against interest rates.
• Dividend yield (dividends ÷ price) tells you what you're getting paid in cash, and it should also beat interest rates — especially in mature, stable companies.
• Price-to-book value helps you avoid overpaying.

These are the three ratios that most directly matter for your investment decisions. When buying or selling, when evaluating a company against a government bond, when deciding whether to hold for the long term — these are the numbers to watch.

I hope this gives you a clear conceptual foundation. In the next chapter, we'll apply these ratios to practical, real-world examples from the market.