Panic-Selling During Iran Will Cost British Investors More Than the Crisis Itself

Since 1984, the FTSE 100 has survived Black Monday (1987, -26%), the dot-com crash (2000-03, -50%), the financial crisis (2008, -31%), the Covid crash (2020, -34%), and the Ukraine invasion (2022, -8%). Every single time, investors who sold into the panic locked in losses. Every single time, investors who held recovered and then some.

The pattern is so consistent it's boring. The FTSE 100 has delivered an average annual return of roughly 7-8% including dividends over the past 40 years. That return includes every war, every oil shock, every financial crisis. The Bank of England's own research on historical returns confirms that equities outperform cash over virtually every rolling 10-year period.

The Iran conflict is real. The Strait of Hormuz disruption is serious. But so was a global pandemic that shut every economy on earth. The FTSE 100 recovered from Covid's 34% crash in less than 18 months. So was the 2022 Ukraine invasion — UK stocks fully recovered within a year.

What makes you think this time is different? That question sounds glib. It's the most important question in investing. If you're looking for perspective on how UK markets have weathered previous crises, our investing guide covers the historical evidence in detail.

The cost of going to cash isn't the 4.75% you earn. It's the recovery rally you miss.

Research from Schroders shows that missing just the 10 best trading days over a 20-year period cuts your total return by more than half. The problem? Those best days almost always occur during or immediately after the worst periods. The biggest single-day gains happen within weeks of the biggest drops.

If Iran announces it's reopening the Strait of Hormuz tomorrow — or Trump announces a deal — the FTSE 100 could jump 5-8% in a single session. That's not speculation. That's exactly what happened when ceasefire rumours circulated during the Ukraine crisis in 2022.

Your cash account pays 4.75% per year. That's 0.013% per day. One good day in the market delivers what cash takes a year to produce. The MoneySavingExpert savings comparison shows the best rates available — and even they can't compete with a single recovery day.

Sitting in cash means you need to be right twice: right about when to sell, and right about when to buy back in. Almost nobody gets both calls correct. For a deeper look at how staying invested works across asset classes, see our investing guide. Those with ISA questions should check our ISA hub before the April 5 deadline.

The psychological appeal of cash during a crisis is powerful. Your balance doesn't go down. But as our cash savings analysis shows, even tax-free cash barely keeps pace. You sleep better. The red numbers stop.

But inflation doesn't stop. CPI is running above the Bank of England's 2% target, and the Iran oil shock is pushing energy costs higher. The Ofgem energy price cap rises on 1 April. Petrol is above 150p.

Your 4.75% easy access account sounds generous. After basic-rate tax (20%), that's 3.80% net. If inflation runs at 3.5% — entirely plausible given the energy shock — your real return on cash is 0.30%. You're treading water, not building wealth.

Higher-rate taxpayers fare worse. At 40% tax, 4.75% becomes 2.85% net. After inflation, you're losing purchasing power. The Personal Savings Allowance gives basic-rate taxpayers £1,000 of tax-free interest and higher-rate taxpayers £500 — but a £50,000 cash holding at 4.75% generates £2,375 of interest. Most of that is taxable. Our tax guide explains how to calculate your actual tax-free savings capacity.

Equities, by contrast, have consistently beaten inflation over any 10-year period in modern UK history. The FTSE 100's dividend yield alone sits around 3.7%. Add capital growth over a full cycle and you're looking at 7-8% nominal returns — roughly double what cash delivers after tax. For those considering fixed-income alternatives, our gilts hub covers how government bonds fit into a diversified portfolio.

Unlike structural economic problems — a housing crash, a banking crisis, a pandemic — geopolitical conflicts tend to resolve faster than markets expect. As our Iran crisis tracker documents, Trump has given Iran until 6 April. That's a deadline that produces one of two outcomes:

1. Iran negotiates and the Strait of Hormuz reopens. Oil prices drop. FTSE 100 rallies 5-10% in days. Cash-holders miss it entirely.
2. Escalation continues but markets have already priced in the worst case. The 11% drop reflects significant fear. Further downside from here requires a scenario worse than what's already expected.

Markets are forward-looking. They don't wait for the all-clear to recover. They start climbing when the situation is still terrible but less terrible than feared. By the time the headlines turn positive and you feel comfortable buying back in, the recovery is half over.

The FTSE 100's reaction to recent diplomatic developments shows this pattern clearly — stocks rallied on even the slightest hint of negotiation progress. The BBC reported that consumer confidence is already reflecting maximum pessimism — which is precisely when markets tend to find their floor.

History shows that geopolitical sell-offs tend to be V-shaped: sharp down, sharp up. The Gulf War in 1990-91 saw the FTSE fall 14% and recover within five months. If you sold at the bottom and waited for "clarity," you missed the entire recovery. Our savings guide is useful for building an emergency fund, but it's not a substitute for a long-term investment portfolio.

If you're invested and worried, there are productive responses that don't involve crystallising an 11% loss:

• Rebalance, don't liquidate. If your portfolio has drifted away from your target allocation because equities fell, this is an opportunity to buy more shares at lower prices — your ISA allowance can shelter the gains, not sell them
• Use your ISA allowance. The 5 April deadline is eight days away. Investing £20,000 into a stocks and shares ISA when the FTSE is down 11% means buying at a discount. Your future self will thank you
• Increase your regular contributions. If you invest monthly via a workplace pension or ISA, the drop means each contribution buys more units. That's pound-cost averaging working exactly as designed
• Check your time horizon. If you need the money within 2 years, it shouldn't have been in equities anyway — crisis or no crisis. If your horizon is 10+ years, this dip is noise

Our ISA guide explains how to make the most of the remaining 2025/26 allowance. For pension contributions, check our pensions hub for tax relief calculations.

The only investors who should genuinely move to cash are those who discover, mid-crisis, that their risk tolerance was wrong all along. That's a portfolio construction problem, not a market timing opportunity.

This article is for informational purposes only and does not constitute financial advice. You should seek independent financial advice before making any investment decisions.