High Price Doesn't Mean Expensive: The One Ratio Every Investor Needs to Know

You're watching the stock market climb for months. Prices are up 40%, 50%, 60%. Every headline screams that the market is at an all-time high. So naturally, you assume it must be expensive — maybe even dangerously so.

But what if I told you that a market up 60% could actually be cheaper than it was at the bottom?

That's not a trick. It's one of the most important — and most misunderstood — ideas in investing. And once it clicks, you'll never look at a stock price the same way again.

📝 Note: This post was written with the assistance of AI. The content reflects my personal learning and understanding and should not be taken as professional advice. Please do your own research and due diligence before acting on anything written here.

🥟 The Samosa That Changed How I Think About Stocks

Imagine your local snack stall sells samosas for ₹10 each. Tomorrow, the price goes up to ₹15. More expensive, right?

Now imagine the samosa is also twice the size. Same crispy shell, but double the filling. Suddenly, ₹15 for twice the samosa is a better deal than ₹10 for the smaller one. The price went up — but the value you're getting went up even more.

Stocks work exactly like this. The price of a share is like the sticker price on the samosa. But what you're actually buying is a slice of a company's profits. And if those profits grow faster than the price, you're getting more for your money — even if the number on the screen looks bigger.

This is the entire idea behind the Price-to-Earnings ratio, or P/E ratio. It's not about what the stock costs. It's about what you're getting for that cost.

📐 What the P/E Ratio Actually Measures

The P/E ratio answers one question: for every rupee of profit this company earns, how many rupees are you paying?

$P/E = \frac{\text{Price per Share}}{\text{Earnings per Share}}$

In plain English: price divided by profit (per share).

• A P/E of 10 means you're paying ₹10 for every ₹1 of annual profit.
• A P/E of 25 means you're paying ₹25 for every ₹1 of annual profit.

All else being equal, lower is cheaper. You're paying less per rupee of earnings.

But here's where it gets interesting — and where most people go wrong.

📉 How a Market Can Rise 60% and Get Cheaper

Between 2004 and 2007, the MSCI World Equity Index — a broad measure of global stock markets — went on a sustained rally. By mid-2007, it had climbed roughly 60% from its 2004 base.

Most people looking at that chart would assume the market had become significantly more expensive over those three years. The price was way up. It must be pricier, right?

But look at what happened to the P/E ratio over the same period:

At the very peak of the market — when prices were at their highest — the P/E ratio was at its lowest. The market was, by this measure, cheaper in 2007 than it had been in 2004.

How? Because corporate earnings grew even faster than prices did. When the denominator (earnings) grows faster than the numerator (price), the ratio falls. You're getting more profit per rupee spent, even though the price tag is higher.

It's the samosa again. Bigger filling, proportionally lower cost per bite.

The insight: A rising price doesn't mean a rising valuation. You always need to ask what you're getting for that price.

🔄 The Reverse Is Just as True

If a stock can get cheaper as it rises, it can also get more expensive as it falls.

Say a company's stock drops from ₹500 to ₹300 — down 40%. That sounds like a bargain. But what if the company's profits collapsed at the same time, from ₹50 per share to ₹15 per share?

$\text{P/E before} = \frac{500}{50} = 10x$

$\text{P/E after} = \frac{300}{15} = 20x$

The stock got cheaper in price. But it became twice as expensive in valuation. You're now paying ₹20 for every ₹1 of profit, compared to ₹10 before. That's not a bargain — that's a trap.

This happens more often than you'd think, especially during economic downturns when company earnings fall off a cliff faster than stock prices do.

⚠️ But Wait — Does Cheap Mean Safe?

Here's the part that keeps this from being too clean: a cheap valuation is not a guarantee of anything.

In the same 2004–2007 example, the global market crashed hard after 2007 — dropping from 160 all the way down to 70 within two years. That's nearly a 55% fall from peak to trough. The Great Recession. The subprime crisis.

And yet, as we just saw, the market was cheap by P/E standards at the peak.

So what happened? The crash wasn't caused by overvaluation. It was caused by excessive leverage — too many investors and institutions had borrowed heavily to ride the rally, and when the US real estate market collapsed, the whole system unwound violently. Cheap or not, forced selling doesn't care about your P/E ratio.

This is the honest, uncomfortable truth about valuation metrics: they tell you a lot, but not everything. A stock or market can be cheap and still fall — sometimes dramatically — if something breaks in the broader system.

Valuation tells you what you're paying relative to what you're getting. It does not tell you what happens next.

🧭 So What Is the P/E Ratio Actually Good For?

Used correctly, the P/E ratio is one of the most useful tools a beginner investor has. Here's what it genuinely helps with:

Comparing two stocks in the same industry. If Zomato trades at a P/E of 80 and Swiggy trades at 40, Zomato is more expensive on this measure. Whether that's justified is a separate question — but now you're asking the right one.

Comparing a stock to its own history. If a company usually trades at 20x earnings and it's now at 12x, something has changed — either the business has gotten worse, or the market is underpricing it.

Getting a rough sense of whether a whole market is stretched. During bubble periods, market-wide P/Es tend to balloon. During crises, they tend to compress. Neither extreme lasts forever.

What it doesn't do well: comparing companies across very different industries (more on that in the next post), or predicting short-term price moves.

✏️ Key Takeaways

• Price is not the same as value. A stock at ₹1,500 is not automatically more expensive than one at ₹500.
• The P/E ratio = price divided by earnings per share. It measures what you pay for each rupee of profit.
• A rising market can be getting cheaper if earnings grow faster than prices.
• A falling market can be getting more expensive if earnings fall faster than prices.
• Cheap doesn't mean safe. Valuation tells you about relative cost, not about what happens next.

Here's the reframe: stop asking "is the stock price high or low?" Start asking "what am I getting for that price?" That one shift moves you from guessing to actually analysing.