Back to the Investment Basics Part 3: Our Marvelous Markets

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

In Part 2, we covered saving, the first of five basics that have served investors well over time. Now that you have money to invest, the next question is where returns actually come from and what that means for how you should invest. That is the subject of Part 3.

Two Ideas That Are Both True

Consider two ideas about the market that seem to point in opposite directions.

The first comes from Warren Buffett, who has argued for decades that people will keep paying for products they value, whatever form money takes. Businesses that serve real needs keep producing profits, and ownership of those businesses keeps producing returns. That is the case for the market’s durability.

The second is a line often credited to Wall Street veteran G.M. Loeb. “Whenever you think you’ve found the key to the market, someone changes the lock.” That is the case for its unpredictability.

So which is right? Both. Markets are robust over long periods and random over short ones, and a good approach has to respect each.

Why Returns Exist at All

It is easy to lose sight of where returns come from when you watch prices move all day. Behind every ticker symbol is a company hiring people, making things, and selling them to customers. Over long periods, the market’s results reflect the profits from that work, and that work rests on people constantly finding better ways to do things.

It often seems as though the good ideas must be running out. So far, they have not. Each generation’s tools, from the printing press to the microchip, make the next round of invention possible, and the companies that turn those inventions into products are what investors own a share of.

Why Leadership Keeps Changing

Even so, no one can tell in advance which companies will benefit most. At any moment there are standout winners and plenty of disappointments, and they can swap places with little warning.

The largest U.S. companies in 2000 included General Electric and Cisco. The leaders today look quite different, and it is a safe bet the list will look different again in twenty years. The people who owned only the leaders of 2000 did not necessarily share in the growth that came after.

The development of the COVID-19 vaccines shows how unpredictable the benefits of innovation can be. The vaccines arrived in under a year, far faster than any before them. But that speed rested on decades of unglamorous research into messenger RNA, work that earned its pioneers the 2023 Nobel Prize in Physiology or Medicine. Much of that earlier research did not obviously reward investors at the time. The payoff was real, but it arrived in a place and at a moment few people would have predicted.

Why Broad Ownership Usually Wins

If it were easy to spot the winners in advance, professional investors would do it consistently. The data suggest they do not. According to the SPIVA U.S. Scorecard from S&P Dow Jones Indices, 79 percent of actively managed U.S. large-cap funds trailed the S&P 500 in calendar year 2025, and 67 percent trailed it in the first half of 2026. Some managers beat the index in any given period. Very few do it reliably, and it is hard to know ahead of time which ones will.

This does not mean investing is hopeless. It means the sensible approach is to accept market returns rather than try to outguess them. Own a broad slice of the market so you participate in the companies that succeed. Diversify across industries, company sizes, and countries so no single disappointment can do much damage. Keep costs low, which we take up in Part 4.

What This Means for How You Invest

Think of owning the whole market as owning an orchard rather than betting on a single tree. You cannot know which trees will bear the most fruit this year, but if you own enough of them, the harvest does not depend on any one. Some seasons are poor, and the orchard is still worth owning.

Prices swing constantly in the short run, and results only start to look orderly over years and decades. That is a reason to stay invested as planned. Since no one knows where the next good season will come from, it is also a reason to diversify.

Accepting that stock returns are both robust and random can also help you stay calmer, or at least a little calmer, when things get rough. If you want to see how this shows up in a portfolio, our post on why a balanced portfolio beats chasing winners goes deeper on structure and rebalancing.

Frequently Asked Questions

Where do stock market returns come from?

Over long periods, they come mainly from the profits of real businesses, paid to owners through dividends and reflected in rising share prices as companies grow. In the short term, prices also move with sentiment, interest rates, and news, which is why the ride is bumpy.

Are stock market returns predictable?

Not reliably. Long-term trends have been upward, but individual years vary widely. The S&P 500 lost 18.1 percent in 2022 and gained 26.3 percent the next year. No one has a dependable way to know in advance which will come next.

What does diversification actually do?

Diversification spreads your money across many companies, industries, and regions so that a problem in any one of them has limited impact on the whole. It does not eliminate risk or prevent losses in a broad decline, but it reduces the chance that a single bad bet defines your results.

Can I beat the market by picking stocks or hiring an active manager?

Some people do in some periods, but it is difficult to do consistently. SPIVA data show that most actively managed U.S. large-cap funds trailed the S&P 500 in both 2025 and the first half of 2026, and the ones that lead are hard to identify beforehand. Many investors are better served by broad, low-cost diversification.

If markets are random, why invest at all?

Because random does not mean directionless. Short-term movements are unpredictable, but over long periods markets have rewarded people who owned businesses through the ups and downs. Investing is a bet on human ingenuity continuing, made sensibly enough that you can stay with it.

Continue the Series

In Part 4: The Price You Pay Matters, we look at how stock prices are set, what they do and do not tell you, and how the costs you pay to invest affect your results.

This article is general education and is not investment advice. Past performance does not guarantee future results, and diversification does not ensure a profit or protect against loss in a declining market. Index returns include reinvested dividends, are for illustrative purposes only, and do not reflect fees, expenses, or taxes. Indices are unmanaged and not available for direct investment. Sources: S&P 500 annual total returns per S&P Dow Jones Indices data; SPIVA U.S. Scorecard, S&P Dow Jones Indices, year-end 2025 and mid-year 2026. Every situation is different, so talk with a qualified professional before making decisions about your finances.