Many people in the UK are losing money by misplacing the details of some of their bank accounts, according to Halifax.
The company's spokesperson, James Clarke, stated that not updating their details with a bank when moving house or getting married can lead to people forgetting about money they may have saved in dormant accounts.
Recent research by the Unclaimed Assets Register estimated that £15.3 billion lies unclaimed in accounts, pensions and shares.
Mr Clarke said: "Generally what will happen is, accounts which have been used for a specific reason say, saving for a holiday or something like that and are pass-book based, the pass-book goes in the bottom of a drawer and people tend to genuinely forget about them.
"In other cases, people move house and don't update their bank with a change of name and address; they don't get statements; and the account gets forgotten about that way."
Halifax provides a number of services to customers across the globe, including insurance and investment products.
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