Forgotten cash ISAs at National Savings and Investments (NS&I) now hold £217 million, according to figures released this week, while millions of Premium Bond prizes and hundreds of millions of pounds in old bank accounts sit unclaimed across the UK. Here is what the numbers show, why money goes missing, and how to check whether any of it is yours.

Key takeaways

• NS&I had 42,973 dormant cash ISAs worth £217 million in 2024/25, an average of about £5,061 each, up from £36.7 million in 2020/21.
• Around £126.8 million in Premium Bond prizes is unclaimed, and only about 11% of the £557 million moved into the government’s dormant assets scheme since 2022 has been reclaimed.
• Tracing lost savings is free, and there is no deadline: NS&I and the My Lost Account service can search on your behalf.

Why everyone is talking about it

“NS&I” was among the most-searched terms in the UK on 30 September, after data obtained by The Telegraph from the state-backed savings provider, and reported by The Independent and others, showed how much money is sitting in accounts nobody has touched for years. The same day, research from comparison site Confused.com put a figure on lost bank balances more widely. With UK inflation rising again and households watching every pound, the idea of “free money” you already own has struck a chord.

The facts so far

NS&I classes an ISA as dormant once there has been no transaction on it for 15 years. On that definition, it held 42,973 dormant cash ISAs in 2024/25, worth £217 million in total. Four years earlier, in 2020/21, there were 8,621 such accounts holding £36.7 million, so the total has grown almost sixfold. Those dormant ISAs earn about 0.25% interest, according to the reported figures. NS&I also holds around £614 million across roughly 1.1 million postal-only savings accounts, where the average balance is about £550.

Premium Bonds add to the pile. NS&I data cited by MoneyWeek shows 2,851,753 unclaimed prizes worth £126,787,100. Nearly all are £100 or less, but 13 are worth £100,000 each.

Beyond NS&I, Confused.com found that more than £557 million was transferred from dormant bank and building society accounts into the government’s Dormant Assets Scheme between 2022 and 2025, and only £62.7 million of it had been reclaimed. People who did trace a lost account recovered £1,011 on average.

Tracing does work. NS&I’s tracing service reunited customers with £201.5 million in 2025, according to the reported figures.

The background

Money rarely goes “missing” in a dramatic way. More often it is a children’s savings account opened by a grandparent, a Premium Bond bought decades ago, or an ISA left behind after a house move. Letters go to an old address, the account stops showing up in any banking app, and after enough years it is simply forgotten. Think of it like a coat left in a cloakroom: the ticket is lost, but the coat is still on the hook with your name on it.

For ordinary banks, balances untouched for 15 years can be passed to Reclaim Fund Ltd under the Dormant Assets Scheme, which uses the money for good causes but must repay the owner whenever they come forward. NS&I is backed by HM Treasury, and its tracing service states there is no time limit on claims.

The topic is sensitive for NS&I. In May it said it would repay about £367 million to up to 34,000 bereaved families after an “operational failure” in tracing the savings of deceased customers. It says affected estates do not need to do anything and expects the payments to be completed in the first half of 2027.

What it means for your money

A forgotten account doesn’t just risk being lost. It also tends to earn very little. The Bank of England held Bank Rate at 3.75% on 17 September, and many savings products pay well above the 0.25% reported on dormant NS&I ISAs.

A simple example: take the average dormant ISA balance of £5,061. At 0.25%, it earns about £12.65 a year. If the same money earned a hypothetical 3.5%, it would make about £177 a year, roughly £164 more, before inflation. And when inflation is running above 3%, money earning 0.25% is losing buying power every year (see what inflation means for your wallet).

Practical steps, all free:

• Use the NS&I prize checker (website or app) with your Premium Bonds holder number. If you don’t have the number, NS&I’s tracing form can help.
• Search for old bank, building society and NS&I accounts in one go at mylostaccount.org.uk. NS&I aims to confirm any accounts within a month of receiving your application.
• Keep a simple list of every account you hold, and update your address with each provider when you move.
• Be wary of anyone who charges a fee to “find” your money or who contacts you out of the blue, since the official routes cost nothing.

As Confused.com’s Tara Evans put it: “Forgotten money does not expire and it belongs to you.” For how interest-rate decisions feed through to savings, see our explainer on rates and savings.

What to watch next

The Bank of England’s next rate decision is due on 5 November. Three of nine policymakers voted for a rise in September, and that decision will shape what savers can earn. Also watch NS&I’s progress on the bereavement repayments, due to finish by mid-2027, and whether the rising dormant balances prompt calls for providers to do more to reach customers. Key dates are in our economic calendar.

This is general information, not financial advice.

Sources

• The Independent (via Yahoo Finance): NS&I savers missing out on £217m in lost accounts
• AOL: Brits urged to make vital dormant bank account check as £557 million sits unclaimed
• MoneyWeek: Unclaimed Premium Bonds prizes
• NS&I: Tracing service brochure
• NS&I: Bereavement claims update (19 May 2026)
• MoneySavingExpert: NS&I to pay £367m to bereaved families
• Bank of England: September 2026 Monetary Policy Summary

Written by The Daily Economy editorial team with AI assistance and checked against the sources above. Read our editorial policy.