Back to the Investment Basics Part 4: The Price You Pay Matters

By Leah Hadley, AFC®, CDFA®. Last updated September 2026.

In Part 3, we described markets as both robust and random. Today we turn to price. What does the price of a stock actually tell you, why are prices so hard to predict, and what does “the price you pay” mean for your own results?

Why Does One Share Cost $763,600 and Another $509.77?

In mid-September 2026, one Class A share of Berkshire Hathaway traded at roughly $763,600. A Class B share of the same company traded at about $509.77. They are two slices of the same business. Each Class A share can be converted into 1,500 Class B shares, and 1,500 times $509.77 is about $764,655, which is right where you would expect.

That is a useful illustration of why the price per share tells you almost nothing on its own. A high share price does not mean a stock is expensive, and a low one does not mean it is a bargain. What matters is what you get for the money, which means the company’s earnings, growth, and risk, compared with the total price the market puts on the whole business.

How a Price Actually Gets Set

A stock’s price is not arbitrary, and it is not a fixed fact either. It is the result of countless decisions made every second the market is open, some driven by careful analysis and some by mood. Analysts, institutional managers, day traders, and everyday investors all place bids and offers, and the price is whatever buyers and sellers agree on when they trade.

Nobel laureate William Sharpe, who helped establish the capital asset pricing model, has put it this way. Security prices are set by human beings trying to assess the future prospects of companies and governments, so a price reflects the average opinion of investors about what lies ahead. His fellow laureate Eugene Fama added that in a market with many competing participants and freely available information, the price at any point in time is a good estimate of a security’s intrinsic value.

That is why market prices can be remarkably efficient in aggregate and still wildly unpredictable from one moment to the next.

Price Versus Value

Behind every share is a real company delivering real goods and services. Its price is continuously reset by what buyers and sellers collectively think the business is worth, based on its fundamentals and on sentiment. A company that keeps beating expectations can see its stock keep climbing, although growth on top of growth gets harder to sustain.

Does that mean price does not matter? Should you be willing to pay any amount for a promising investment? No. A great company can still be a poor investment if you pay too much for it. Warren Buffett has made this point for decades, and Sharpe has cautioned that returns in any single period can land far above or far below what you expect, a risk that many investors forget while prices are climbing.

Where Valuations Stand Today

One common way to gauge whether the overall market is priced richly is the Shiller CAPE ratio, which compares stock prices with average inflation-adjusted earnings over the past ten years. As of September 18, 2026, it stood at about 40.9. Its long-run average is about 17.4, and its all-time high was about 44.2 in December 1999, just before the dot-com bubble burst.

What should you do with that? Be careful. Historically, high starting valuations have been associated with lower returns over the following decade, and it is worth knowing that expectations should be modest. But valuations are a poor timing tool. Markets have stayed expensive for long stretches, and no one has a reliable way to say when they will not be. Selling everything because a ratio looks high is another way of trying to predict the unpredictable.

The better response is the one we come back to throughout this series. Diversify across regions, sizes, and asset types so you are not leaning entirely on the most expensive corner of the market. Keep enough in stable holdings to cover near-term needs. And rebalance on schedule, which trims what has run up and adds to what has lagged.

The Other Price You Pay

The price of the investment itself is only part of the picture. The cost of owning it matters just as much, and unlike market returns, you can control it.

Morningstar’s 2025 fund fee study found that the average asset-weighted expense ratio paid by fund investors fell from 0.80 percent in 2006 to 0.32 percent in 2025, saving investors nearly $6.8 billion in a single year. That is real progress, but costs still vary widely from fund to fund, and they are charged every year whether the fund does well or not.

Here is why it adds up. As a hypothetical illustration, $100,000 growing at 7 percent a year for 30 years would reach about $761,000. Pay an extra one percentage point a year in costs, so that it grows at 6 percent instead, and it reaches about $574,000. That is a difference of roughly $187,000, from a cost that never shows up as a line item on your statement.

This illustration is hypothetical, does not represent any actual investment, and does not account for taxes or contributions. It is meant to show how a small annual cost compounds, not to project a result.

What to Do With All of This

So does price matter? Yes, but not because you can outsmart it. It matters because what you pay for a business, and what you pay to hold it, both come out of what you keep. Once you understand how prices are set, the goal shifts from beating the market to owning it sensibly. Invest broadly, diversify widely, keep costs in check, and stay invested, so that the growth investors expect from the overall market has time to become returns.

Frequently Asked Questions

Does a high stock price mean a stock is expensive?

No. Share price alone says nothing about how richly a company is valued, because it depends on how many shares exist. Berkshire Hathaway’s Class A shares trade near $763,600 and its Class B shares near $509.77, yet they represent the same company. Valuation depends on price relative to earnings, growth, and risk, not on the number of dollars per share.

How are stock prices determined?

By buyers and sellers. Every trade reflects what one person is willing to pay and another is willing to accept, and the latest trade sets the current price. In aggregate, this process incorporates a huge amount of information, which is why prices are efficient overall and difficult to beat.

What is the Shiller CAPE ratio, and should I worry about it?

The CAPE ratio compares stock prices with ten-year average inflation-adjusted earnings. It stood near 40.9 in September 2026, well above its long-run average of about 17.4. High readings have historically been associated with lower returns over the next decade, but they are unreliable for timing. They are a reason to diversify and keep expectations realistic, not to abandon a plan.

How much do investment fees matter?

More than most people expect, because they compound. A hypothetical difference of one percentage point per year on $100,000 over 30 years is about $187,000 in ending value. Look at expense ratios, trading costs, and any advisory fees, and make sure the value you receive justifies each one.

Is it a bad time to invest when valuations are high?

Waiting for a better price has its own cost, since markets can stay expensive for years and you may miss gains while you wait. For long-term goals, most people are better served by investing on a schedule and diversifying, and by keeping money they will need soon out of the market.

Continue the Series

In the final post, Part 5: Patience and Personal Persistence, we cover the two essentials that are about you rather than the market.

This article is general education and is not investment advice. Past performance does not guarantee future results. Share prices are approximate, from mid-September 2026, and are for illustration only, not a recommendation to buy or sell any security. The Shiller CAPE ratio is as reported by multpl.com as of September 18, 2026. Fund expense data is from Morningstar’s 2025 U.S. Fund Fee Study. The 30-year example is hypothetical and is not a projection. Every situation is different, so talk with a qualified professional before making decisions about your finances.