In investing, risk usually means the chance that an outcome differs from what you expect, including the chance of losing money. The most common measure is volatility, which describes how widely prices swing over time. Risk also includes the chance of a permanent loss, such as a company failing, and the chance that the outcome does not meet your goal, even when no price is lost.
This guide explains why higher expected returns usually come with bigger swings, how to judge whether a return justifies the risk, and how to tell your risk tolerance from your risk capacity. The examples use invented figures. They illustrate the ideas and do not describe the results of any real asset.
What is risk in investing?
Risk is uncertainty about the outcome. Two investments can have the same expected return but very different paths. One may move gently, while the other swings sharply, so that a holder might see large gains and large losses along the way.
Volatility captures the size of those swings, and it is the most common way to measure risk in market data.
Volatility is not the whole story. An asset can be calm for years and then suffer a permanent loss, because the company behind it failed. Another can swing wildly and still recover fully over a long period. When you assess risk, ask how large the swings could be, what could cause a permanent loss, and whether the outcome could fall short of a goal you care about.
Why do returns and risk usually go together?
Investors generally require extra return for taking on uncertainty, so assets with more volatile outcomes tend to offer higher expected returns over long periods. This link is a tendency, not a promise. Some risky assets disappoint, and some safer ones perform well in particular periods. The relationship describes what investors expect on average, not what each holding will deliver.
The table below uses illustrative figures for two hypothetical assets. Asset A is a deposit with a fixed return. Asset B is a broad share portfolio with a higher expected return and much larger swings. The figures are invented and are not historical data.
| Asset | Expected return a year | Typical swing (volatility) | Illustrative bad year |
|---|---|---|---|
| A: fixed deposit | 3% | Very small | +3% |
| B: broad share portfolio | 8% | Around 15% | −20% |
Asset B offers a higher expected return, but the bad year shows the price of that return. A holder of B who needed the money in that year would have lost a fifth of the value, while a holder of A would have been unaffected. Neither result is a forecast. The example shows why expected return must always be read alongside the range of possible outcomes.
How do you judge whether a return is worth the risk?
Compare the return with the risk taken, and check whether the return survives costs, taxes and inflation. A high average return with a fall you could not tolerate may be a poor match for your goals, even if it looks good on paper.
The question is not only how much an asset might earn, but how much you could lose on the way and whether you could hold through that loss.
One practical test is to ask what the worst year in the expected range would look like in money terms, and whether you could accept it without selling at the bottom. Another is to compare the expected return with a safer alternative after inflation. If the extra return is small for a large increase in swings, the risk may not be worth taking. If the return is large and the swings are manageable, the trade-off may suit your situation better.
What is your risk capacity?
Risk tolerance is how you feel about losses. Risk capacity is how much loss your finances can absorb without damaging your goals. Both matter, and they often point in different directions for the same person, so judge each one honestly.
Someone may feel comfortable with large swings but have a short timeline, an unsteady income or no emergency fund, which reduces their capacity for risk even though their tolerance is high.
Capacity depends on the time until you need the money, the stability of your income, your other savings and any debts. A person who will need the money within a year has little capacity for shares, however confident they feel. A person with a long timeline, a stable income and a cash buffer has more room to hold risky assets through a downturn. Judge both sides honestly before you choose a mix.
What does a bad year look like for you?
Ask what a bad year would look like in money terms, and whether you could live with it. Use figures from your own situation, such as a fall of 20 percent on a sum you may need, rather than an abstract percentage. The question is concrete, and the answer tends to be more honest than a score.
A useful exercise is to imagine that the investment has fallen by a set amount six months after you bought it, and to write down what you would do. If the honest answer is to sell, the risk is probably larger than your tolerance. If the answer is to wait, you may have room for more volatility. Revisit the exercise after a real market fall, if one occurs, because the answer given in calm conditions can differ from the answer given during one.
Why is volatility not always the right measure?
Volatility measures how much prices move, but it can understate the risk of a holding that stays calm until it fails. A stable-looking asset can carry a serious risk of permanent loss, and that risk does not show up in past price swings.
Consider a company whose shares move little for years and then lose most of their value after a problem with its accounts is revealed. Its volatility before the event looked low, yet an investor could still lose most of the money. Checking the business, the debt and the way the company is run can matter more than a calm chart.
Common mistakes
Looking only at the average return. Average returns hide the path. Check the range of outcomes, not just the midpoint.
Confusing feeling brave with having capacity. Tolerance and capacity are different. A short timeline limits the risk you can take regardless of mood.
Assuming that risky means guaranteed to pay. Higher expected returns are not guaranteed. A risky asset can disappoint for years.
Checklist
- Write down the expected return and the range of likely outcomes for each option.
- Check how large the bad year could be, in money terms, for your holding.
- Compare the extra return with the extra swings, after costs and inflation.
- Assess your tolerance for losses honestly, using a real past example if you have one.
- Assess your capacity: timeline, income stability, cash buffer and debts.
- Match the mix to the lower of the two, not the higher.
- Review the choice when your goals or circumstances change.
Key takeaways
Risk in investing is uncertainty about outcomes, usually measured by volatility, and it includes the chance of permanent loss. Higher expected returns tend to come with larger swings, but that link is a tendency rather than a promise. A return is worth its risk only if you could hold through the bad years and it survives costs and inflation. Your risk capacity, which depends on your timeline and finances, limits the risk you should take whatever your mood.
This guide is for general information, not financial advice. See the disclaimer.