Millions of savers across the United Kingdom could be unwittingly missing out on significant sums of money, with new analysis revealing a staggering hidden cost to holding cash in low-interest accounts.
The Silent Erosion of Savings
Fresh research from Fidelity International has uncovered that UK households collectively possess approximately £1.88 trillion in cash deposits. However, the majority of these savings have been generating returns that fall considerably short of inflation, leading to a substantial erosion of purchasing power.
Official statistics from the Office for National Statistics indicate that inflation finished 2025 at 3.4%, while Bank of England figures show the average easy-access savings rate stood at a mere 1.94% throughout the year.
The £7 Billion Sleep Tax
Fidelity's calculations reveal that households forfeited nearly £7 billion to inflation whilst they slept last year. This remarkable figure emerges from the fact that UK adults spend around 38% of their time asleep, during which their cash savings continued to lose real value against rising prices.
The analysis shows that assuming 70% of household savings sit in easy-access accounts and 30% in fixed-rate arrangements, savers generated approximately £45.6 billion in interest during 2025 – representing an average return of 2.43%.
However, after accounting for inflation, the genuine value of cash savings actually dropped by roughly £17.6 billion throughout the year. The portion lost during sleep hours amounts to almost £7 billion, equating to approximately £122 per adult across the nation.
Fixed-Rate Versus Easy-Access Accounts
While fixed-rate accounts performed better with an average return of 3.56%, easy-access products continue to be the preferred option for most savers despite their inferior returns. This preference for liquidity comes at a significant cost when inflation outpaces interest rates.
Marianna Hunt, Personal Finance Specialist at Fidelity International, commented: "Inflation is a silent threat to savers with many people seeing the real value of their cash go backwards. With inflation rising again at the end of the year and remaining above target, our analysis underlines how even relatively modest inflation can continue to erode savings when returns on cash fail to keep pace."
The Long-Term Danger of Excessive Cash Holdings
The research also highlights the longer-term peril of relying too heavily on cash savings. Examining every rolling 10-year period between 1988 and 2025, Fidelity found that investing in UK stocks beat inflation 95% of the time, compared with just 58% for cash savings.
Ms Hunt added: "Holding some cash is essential. For most people, having three to six months' worth of essential spending in cash provides an important safety net, and many retirees sensibly hold larger cash buffers to manage short-term needs and market volatility."
"The risk comes from holding too much cash for too long. As our analysis shows, when savings rates fail to keep pace with inflation, large cash balances can quietly lose value over time – potentially undermining long-term financial security."
The Alternative Investment Scenario
The figures also illustrate what savers might have earned through alternative approaches. Global stock markets experienced a strong year in 2025, with the MSCI World Index returning around 13% in sterling terms.
Fidelity estimates that if just a quarter of UK household cash savings – approximately £470 billion – had been invested instead, the real value of savers' money could have grown by around £44 billion, even after accounting for inflation.
This includes almost £17 billion of growth while people slept. Ms Hunt noted: "When money is invested, it has the potential to keep growing even while you sleep – working in the background while you rest, rather than quietly losing value to inflation."
The research serves as a stark reminder of the importance of regularly reviewing savings strategies and considering diversified approaches to protect against the silent erosion of purchasing power caused by inflation.
