Cash is risky, the stock market is volatile, and why that distinction matters in 2026

Volatility is short-term price movement; risk is the chance of not meeting your goal. They are not the same thing and why it matters in 2026

Definitions

Risk is what you see when there is any investment advert in the uk. “Capital is at risk”, “Stocks may go up as well as down”. “You may get back less than you invest”, and broadly it’s true but it is not likely when investing in a broad index fund. Losing all your money would require the entire stock market and thus all business to collapse, losing your investments is the least of your problems, it would be a global existential crisis. You may get hit by a bus when crossing a busy road tomorrow. It could happen but it’s unlikely as there are traffic lights, speed limits, horns, lights, zebra crossings - lots of signals.

Volatility is short-term price movement; risk is the chance of not meeting your goal. Volatility is what they mean when they say risk. The day-to-day value of individual stocks will move up and down as the folks on Wall Street and the stock exchanges around the world will look for an edge to make money on gaps high-tech computers will highlight. Apple recently dropped 10% when they announced on an earnings call they were using up some of their back-storage of chips during the AI ram shortage. It’s up 15% year to date and up 114% over 5 years as of 8th of August 2026.

Why cash feels safe but isn’t

Cash held in a bank is protected by the FSCS, that’s the Financial Services Compensation Scheme which protects and guarantees your deposits up to £125k per institution (some banks are just brands within the same institution such as First Direct and HSBC). Which means if your bank goes bust, the scheme will foot the bill and return your money at some point in the future.

So that sounds great. Let’s assume your main account pays no interest (typical, as of 2026 in Barclays, Starling and Monzo to name a few), put you are a savvy saver and move your excess cash from your budget on payday each month into an attached savings account, lets assume that’s 2.5% interest, for the sake of this point, some accounts today have introductory rates that last 6 months like the 7.1% at Zopa¹, but over a longer period of time it’s likely 2.5% is generous.

Your mortgage is likely to be nearer 4% though as of August 2026 where the Bank of England² opted to keep the base rate at 3.75%, mortgages cost more because banks have staff, shareholders, risk, and profit to make.

So whilst your money may feel like it grows each month, it’s actually losing purchasing power. £1000 in your bank today won’t buy you the same size/amount/quality of product in 10 years time.

This is inflation. Inflation according to the Office for National Statistics (ONS) report in June 2026³ (new figures are due late August) was that inflation was 2.6, having slowed from 2.8 in May. These figures ignore housing costs, it’s 2.8% slowed from 3.0% in May with housing included.

Note: I saw slowed here, rather than down. Deflation is where the costs of goods drop in price, but 2.6% from 2.8% is not a drop in cost, it’s like a car travelling at 28 mph slowing to 26 mph - if it’s heading towards a brick wall, it’s still going to hit it - just with a very slightly less horrific outcome. The Bank of England’s target is 2% and you have to go back to 2020 for the figure to be below their target.

When Cash is king

Cash is important though, people are generally encouraged to have between 3-6 months of expenses held in easy-to-access cash as an emergency fund, when the washing machine goes pop, or you lose your job, or your zero hours contract has zero hours. Inflation is a tax or cost on that convenience, so any bank interest at all is helpful in making that convenience last longer. Check it every 6-12 months to see if your emergency fund would still cover your essential bills - Council Tax has seen 5% increases, if you’ve remortgaged to a higher rate so your monthly payment has increased that 3 months can quickly become just 2 months.

Inflation is the tax or cost for the convenience of having cash.

For short term goals, like a wedding, or a new bike, having some cash is important, because if it was all in the stock market and there was some volatility in the price that day, your £30k might look like £25k or worse at the exact moment you need it, a week later it might be £40k but paying your live band or venue on time is important.

Why the stock market feels risky but isn’t really

Financial organisations have to tell you the market is risky because the Financial Conduct Authority (FCA) tells them to. But the reality, at least historically is a bit different. If you don’t need to cash for that short term purchase, you can be much more flexible about when you might need to sell and withdraw some of you money and can choose to sell when the market is up, rather than down. Historical performance is no guarantee of the future of course, but years of history show a pattern.

Historically, a global index fund⁴, that is a fund that is invested in thousands of companies around the world, with a weighting to the fact the US stock market, and those big tech companies have been growing in value for a number of years, has since growth of around 8 or 9% per year. This doesn’t include inflation, so lets be generous and include 2.8% as inflation and another 0.2% for fees, account costs etc. We’ll take the lower 8% figure for this example. So 8 minus 2.8 minus 0.2 is equal to 5. So if we assume, on average, over the long term, the global stock market will grow 5% We can see the impact of compounding interest over time.

8% stock market return minus inflation and fees is much more like 5%

Not all years will be 5% sometimes 26% sometimes minus 10%, this is the volatility at play.

Compared to cash the difference is stark.

Remember cash interest is assumed 2.5% before inflation and if we use the same 2.8% we use for stocks (so -0.3% in real terms) this is the difference on £1000 over these time periods (assuming monthly compounding at our fixed percentages (-0.3%, 5%) for simplicity, values would differ in real life, as life is not average)

Asset	3 years	5 years	10 years	15 years	20 years
Cash	£991.03	£985.09	£970.40	£955.93	£941.68
Stocks	£1,157.63	£1,276.28	£1,628.89	£2,078.93	£2,653.30

That’s approximately £1700 difference over twenty years in real terms, on just £1000, imagine the difference if you lump sum was £10k or £100k, but most people it’s mostly likely to be regular contributions such as £250 a month.

Asset	3 years	5 years	10 years	15 years	20 years
Cash	£9,951.71	£15,874.85	£30,527.91	£44,962.48	£59,181.84
Stocks	£10,829.95	£18,229.72	£40,219.68	£68,285.08	£104,104.42

That’s about £45k difference, again in real terms, for investing regularly for the long term in a global index fund.

Where your personal circumstances matter

Missing out on the time horizon matched with growth that beats inflation consistently is what real risk is, ignoring the intra-day volatility labelled as risk. So next we’ll cover the different investment vehicles and why a blend is important.

If you are approaching retirement having gained all this growth, it’s important to plan how to withdraw and seeking financial advice from a regulated professional can become useful to avoid sequencing risk or withdrawing on a down market can cost more than you think.