Understanding Inflation and How to Protect Your Portfolio

What Is Inflation and Why Does It Matter to Investors?

Inflation is the general rise in the price level of goods and services over time. When inflation is running at 3 per cent per year, something that costs £100 today will cost £103 next year. Over 20 years at that rate, it will cost approximately £181. This erosion of purchasing power is the investor's silent enemy — it quietly diminishes the real value of savings and investments that do not keep pace with rising prices.

In the UK, inflation is measured primarily by the Consumer Prices Index (CPI) and the Retail Prices Index (RPI). The Bank of England targets a CPI inflation rate of 2 per cent per year. The 2022 to 2023 inflation surge — which saw UK CPI peak above 11 per cent — was a painful reminder that inflation can deviate dramatically from target and have a significant real impact on financial wellbeing.

How Inflation Affects Different Investments

Different assets respond very differently to inflation. Cash and fixed-rate savings accounts are the most vulnerable — if your cash earns 2 per cent interest while inflation runs at 4 per cent, your purchasing power is falling by 2 per cent per year. Fixed-rate bonds suffer similarly: a bond paying a fixed 3 per cent coupon becomes less attractive when inflation rises above that level, which is why bond prices fall when inflation expectations rise. Equities have historically provided the best long-term protection against inflation because companies can raise prices as their input costs rise, passing inflation through to profits and ultimately to shareholders. Real assets — property, infrastructure, commodities — also tend to hold their value or rise with inflation.

Equities as an Inflation Hedge

Over the long run, equities — particularly diversified global equities — have been the most effective way for UK investors to stay ahead of inflation. The real return from global equities — that is, the return above inflation — has averaged approximately 4 to 6 per cent per year over very long periods. This means a broadly invested global equity portfolio should grow faster than inflation, increasing your real purchasing power over time. However, equities can lag inflation significantly in the short run, particularly during the stagflationary environments where high inflation coincides with weak economic growth.

Index-Linked Gilts and Bonds

UK government index-linked gilts are specifically designed to protect against inflation. Both the coupon payments and the principal are linked to the RPI, ensuring that the real value of your investment is preserved. Index-linked gilt ETFs, such as the iShares £ Index-Linked Gilts ETF, provide diversified exposure to the entire index-linked gilt market and are available within Stocks and Shares ISAs. They are particularly appropriate for investors who prioritise capital preservation and inflation protection over growth.

Real Assets: Property, Infrastructure, and Commodities

Property values and rents tend to rise with inflation over the long run, making REITs a useful inflation hedge. Infrastructure assets — toll roads, airports, utilities — often have contractual price escalation clauses linked to inflation. Commodities including gold and oil tend to rise during inflationary periods. A diversified portfolio that includes some allocation to these real assets can provide additional inflation protection beyond what equities alone offer.

Building an Inflation-Resistant Portfolio

For most UK investors, the core of the portfolio — 60 to 100 per cent of equity allocation — in a global equity index fund already provides substantial long-run inflation protection. Adding a modest allocation to index-linked gilts, REITs, and perhaps gold can enhance resilience during the specific inflationary environments when equities themselves struggle. The key is maintaining a meaningful equity allocation throughout your investment life — cash savings, while feeling safe, are the surest way to see inflation erode your real wealth over time.