The honest summary of risk and reward in investing is shorter than most articles on the topic. Investments that have historically produced higher returns have also produced bigger ups and downs along the way. Investments that don’t move around much don’t make you much money. That trade-off is the whole game, and almost every investing decision you’ll make is some version of choosing where on that scale to sit.
The trouble is that the word “risk” gets thrown around in finance with very little precision, and most people end up with a vague sense that investing is dangerous without a clear idea of what the danger actually is. This post is about getting that picture clearer, because once you understand what risk means in practice, you stop being scared of the wrong things and you start being sensible about the right ones.
What risk actually means
In ordinary English, “risk” usually means the chance of something bad happening. In investing, it means something more specific and slightly less alarming: the size of the ups and downs your portfolio goes through on the way to its eventual destination.
A safer investment is one where the value moves around in a small range. A cash savings account, for instance, gives you a fairly predictable amount each year. You won’t get rich, but you won’t open your statement to an unpleasant surprise either.
A riskier investment is one where the value can swing widely. Global equities, for example, might return 25% in a good year and lose 30% in a bad one. Over a long period, the average works out to something positive, but the journey is bumpy.
The key distinction is between volatility (how much the value moves around in the short term) and permanent loss (actually losing money you’ll never get back). These are not the same thing, and confusing them is the cause of most bad investing decisions.
A global equity portfolio that falls 30% in a market crash has not, in any meaningful sense, lost you 30% of your money. It has lost 30% of its value temporarily. If you don’t sell, and the market eventually recovers (it always has), you haven’t lost anything. The “loss” was on paper. It only becomes real if you act on it.
Permanent loss, by contrast, comes from things like investing your whole pot in a single company that goes bust, or buying a fund whose strategy genuinely fails over decades. Those losses don’t recover. The diversified, long-term, low-cost approach this site is built around is specifically designed to avoid them.
Risk and reward in investing: the trade-off in numbers
Here’s roughly what different asset classes have produced historically, in real terms (after inflation):
- Cash: 0% to 1% per year, with essentially no volatility but real losses to inflation in many years.
- UK government bonds (gilts): 1% to 2% per year, with modest swings.
- Global equities: 5% to 7% per year on average, with frequent ups and downs of 20% to 40%.
The pattern is consistent. The more an investment’s value bounces around in the short term, the higher its long-term return has tended to be. This isn’t a coincidence. The extra return is, in a sense, what the market pays you for being willing to sit through the ride.
If you’re not willing to sit through the ride, you don’t get the return. That’s the whole bargain. People who pull their money out every time markets fall end up with cash returns, because they keep flipping back to cash at exactly the wrong moments.
The thing most people get wrong about risk
When ordinary investors talk about “playing it safe”, they usually mean holding cash or near-cash assets. This feels safe because the number on the statement doesn’t drop.
But over long periods, cash is one of the riskiest things you can hold, because inflation eats it. £10,000 left in a current account in 2005 had about half the spending power by 2025. That’s not visible on the statement, which still says £10,000. But the money has quietly lost half its real value, and there’s no chart that shows it.
This is the difference between nominal risk (the number on your statement going down) and real risk (your actual purchasing power eroding). Equities are riskier in nominal terms but, over long enough periods, much safer in real terms. Cash is the opposite: stable in nominal terms, slowly devastating in real terms.
For someone investing for a goal that’s 20 or 30 years away, holding everything in cash is, by far, the riskier choice. It just doesn’t feel like it, because the danger is invisible.
How to think about your own risk tolerance
There’s a financial industry version of “risk tolerance” that involves filling in questionnaires and getting scored. The questionnaires are fine, but they tend to overcomplicate something simple.
A more useful test is this: how would you feel, and what would you do, if your portfolio fell 30% next year?
If the honest answer is “I’d probably sell to stop the bleeding,” your real risk tolerance is lower than your aspirational one, and you should hold less in equities than you might otherwise want to. There’s no point owning a high-equity portfolio if you’ll bail out at the bottom of the next crash. You’ll lock in the loss without ever capturing the recovery.
If the honest answer is “I’d hate it but I’d hold,” you can probably handle a fairly equity-heavy portfolio.
If the honest answer is “I’d see it as an opportunity to buy more,” congratulations, you’ve already absorbed most of what this site is trying to teach.
The right risk level for you isn’t the one that maximises your potential return. It’s the one you can actually stick with through a bad year. A portfolio you abandon at the worst moment will always underperform a slightly more conservative portfolio you keep.
A simple way to size risk
For most long-term investors, the practical question becomes: how much should I have in equities (riskier, higher long-term return) versus bonds and cash (less risky, lower return)?
The classic rule of thumb, often called the “100 minus your age” rule, suggests holding a percentage in equities equal to 100 minus your age. So a 30-year-old would hold 70% equities, a 60-year-old 40%. It’s crude, but as a starting point it captures something true: the longer your time horizon, the more volatility you can absorb.
Two refinements are worth making.
First, the rule needs adjusting upward for most people now. Lifespans have grown, retirement is longer, and bond yields are still relatively low. A more current version might be “110 minus your age” or “120 minus your age” for someone with a long horizon and good earnings security.
Second, the right number depends on your actual circumstances, not just your age. Someone with a stable salaried job, no debt, and a decent emergency fund can afford to take more equity risk than someone whose income is precarious. The portfolio doesn’t exist in isolation, it sits alongside the rest of your financial life.
For someone in their 30s or 40s with a reasonable safety net and a 20+ year horizon, an 80% to 100% equity allocation is defensible. For someone in their late 50s within sight of retirement, dialling that down to 50% to 60% equities makes sense, mostly to reduce the risk of a bad market in the years just before they start drawing down.
The risks worth worrying about, and the ones that aren’t
Genuine risks worth taking seriously:
- Holding too much in any single share or sector. Concentration is where permanent loss comes from.
- Investing money you’ll need within five years. Short horizons don’t give markets time to recover from bad spells.
- Paying high fees that compound away your returns over decades.
- Behavioural risk: panic-selling at the wrong moment, or chasing last year’s winning fund.
Risks that get talked about a lot but matter much less:
- A market crash next year. Yes, possibly. Over 30 years, though, several crashes are statistically certain, and the historical record shows portfolios recover. The crash isn’t the risk; selling during the crash is.
- A specific country’s economy struggling. Global diversification handles this automatically.
- Picking the “wrong” tracker fund. As long as it’s broadly diversified and cheap, the choice between two reasonable global trackers is almost meaningless to your long-term outcome.
The popular media tends to focus on the dramatic risks (crashes, recessions, headlines) and ignore the slow ones (fees, inflation, behavioural mistakes). The slow ones, in practice, do far more damage to most portfolios.
The boring conclusion
Investing isn’t dangerous in the way headlines suggest. The actual risks are mostly behavioural: people taking on too much equity risk and panicking out at the bottom, or taking on too little and getting eroded by inflation, or paying too much in fees and never noticing.
A diversified, low-cost, long-term portfolio with an equity allocation that genuinely matches your nerve is, on the historical evidence, one of the safer things you can do with your money. The volatility is real, but it’s the price of admission, not the danger itself.
Pick the level of bumpiness you can actually live with, contribute regularly, leave the rest alone, and let time do the work. That’s almost the whole answer.
This article is for information and education only and does not constitute financial advice. Investments can fall as well as rise in value and you may get back less than you invest. Past performance is not a reliable indicator of future results.