Nearly 43,000 dormant Individual Savings Accounts (ISAs) held with National Savings and Investments (NS&I) contain more than £217 million, new figures for 2024/25 show. The accounts, opened before 2011, are classed as dormant after 15 years without any customer transaction.
What counts as a dormant ISA?
NS&I, the savings provider backed by HM Treasury and the Labour Party government, defines an ISA as dormant once 15 years have passed since the account holder last carried out any transaction. That means accounts opened before 2011 and untouched since then now fall into this category.
The total value of these forgotten accounts has now surpassed £217 million, according to data recorded in the 2024/25 financial year.
Experts warn of missed interest
Alice Haine, of Hargreaves Lansdown, said: “While money held in a dormant account may continue to accrue interest, depending on the provider’s terms, the rate may be very low or remain at the original level until the funds are reclaimed.”
Caitlyn Eastell, of MoneyFacts, said savers with dormant NS&I ISA accounts could be missing out on more competitive returns elsewhere. “For savers, a forgotten account isn’t just forgotten money, it could be missed interest,” she said.
“This is particularly relevant given that the savings market is currently offering some of the most attractive returns seen in years, with top-paying savings accounts and cash ISAs exceeding 5pc.”
Calls for better customer tracing
Martyn James, a consumer rights expert, said banks such as NS&I should be doing more to locate lost customers, adding that letters were an “antiquated” means of correspondence.
He said: “It’s extraordinary that in 2026, the old process of sending a few letters at the 15-year point of account inactivity should be all that a business does to find a customer.
“While cold-calling or emailing might set alarm bells off for those justifiably worried about fraud, there are other inexpensive methods that can be used to find missing customers.”
How NS&I responds
An NS&I spokesman said: “We provide information online and through our call centre on how to do this.
“We also regularly publicise details of unclaimed prizes and encourage customers to use our prize checker, to register to have Premium Bonds prizes paid directly into their bank account, update their contact details, and use our tracing service to track down lost accounts.”
The spokesman’s comments follow the warning that affected customers could reclaim their funds by contacting NS&I directly, using the provider’s online tools or call centre services.
