Risk and Return in the Stock Market

What this means

The stock marketThe network of exchanges and brokers where investors buy and sell shares of publicly traded companies. is not where companies raise money day to day. It is where investors trade shares with each other. Every share you buy is a share someone else decided to sell, at a price the two of you agreed on.

When you sell for more than you paid, the difference is a capital gainThe profit from selling an asset for more than its purchase price.. When you sell for less, it is a capital lossThe loss from selling an asset for less than its purchase price.. Both are real outcomes of the same activity, and any honest account of investing has to give them equal billing.

Notice what a trade implies. The buyer thinks the shares are worth holding at that price; the seller thinks the cash is worth more. Both are looking at the same public information and reaching opposite conclusions. That disagreement is what makes a market, and it should make you skeptical of anyone claiming a stock is obviously a good buy at the current price.

Now compare that to a very different instrument. A U.S. Treasury bondA debt security issued by the United States federal government, considered among the safest investments because it is backed by the government's taxing authority. pays a stated rate of interest on a set schedule and returns the principal at maturity. Hold it to maturity and you know your nominal return at the moment you buy. Buy a stock and you do not know your return until you sell, and it may be negative.

That gap is the whole idea. Investors dislike uncertainty, so they will not accept the same expected payoff from a risky asset that they accept from a safe one. To attract buyers, riskier assets must offer a higher expected return. The extra expected return demanded for bearing that risk is the risk premiumThe additional expected return investors demand for holding a riskier asset instead of a safer one.. Over long historical periods, broad stock holdings have delivered higher average returns than Treasury bonds, and this is why.

Read that claim precisely, because it is easy to overstate. "Higher on average in the long run" is a statement about a distribution over many companies and many years. It does not promise that any particular stock beats bonds, and it does not promise that stocks beat bonds over any particular stretch. There have been multi-year periods where stocks lost value and Treasury holders came out ahead. If risk did not sometimes materialize as loss, it would not be risk, and there would be no reason for the premium to exist.

One more thing to be careful about when you measure. The rate of returnA return measured as a percentage of the amount originally invested, over a stated period. on a stock has two components: the change in price and any dividends received. Ignoring dividends understates the return, sometimes badly, especially for mature companies that distribute a large share of profits.

Why it matters

You will meet this trade-off long before you have money to invest. Every claim that some asset offers high returns with little risk is asking you to believe that other investors have collectively overlooked free money. Sometimes markets are wrong, but the default assumption should be that unusually high expected returns come attached to unusually high risk that you have not yet identified.

The framing also clarifies why time horizon matters so much. Money you need next year and money you will not touch for forty years face different problems. A short horizon leaves no room to recover from a bad stretch; a long one does, which is why the composition of retirement accounts typically differs from the composition of an emergency fund. That is a statement about matching risk to when you need the money, not a recommendation about what to buy.

Try it

1. Pick one company from the current Dow Jones Industrial Average. Choose a clean three-year window ending on a recent date, and write down the exact start and end dates you will use.
2. Look up the share price on the start date and the end date. Record your source. Check whether any stock split occurred in your window, since a split changes the share count and will corrupt your calculation if you ignore it.
3. Compute the price return: end price minus start price, divided by start price, times 100. This is your percentage return from price change alone over the full three years.
4. Look up the dividends the company paid per share across those three years and total them. Compute dividend return as that total divided by the start price, times 100. Add it to your price return to get total return.
5. Convert your three-year total return into an annualized figure so it can be compared fairly to an annual interest rate. Take the ratio of ending value to starting value, raise it to the power of one third, subtract one, and express as a percent.
6. Now build the comparison. Look up the yield on a three-year U.S. Treasury security as of your start date. That is roughly what an investor could have locked in at the same moment with far less uncertainty. Record the figure and the source.
7. Compare the two annualized numbers directly. Which was higher for your company over your window? Compute the difference in percentage points.
8. Pool the class results. Put every student's company, annualized stock return, and the Treasury yield on the board. Count how many companies beat the Treasury and how many did not. Compute the class average stock return and compare it to the Treasury yield.
9. Interpret the pooled data in writing. Did every company beat the safe alternative? If not, does that contradict the claim that stocks earn more on average in the long run? Explain what the phrase "on average in the long run" does and does not assert.
10. Stress-test your own result. Shift your three-year window forward or backward by one year and redo steps 2 through 5. Report how much the answer moved. Write one paragraph on what this sensitivity implies about drawing conclusions from any single three-year window.

Check yourself