More than £366 billion is languishing in UK current and savings accounts earning returns of 1% or less, according to analysis.
In January, Yorkshire Building Society and data consultancy CACI estimated there was £380 billion held in accounts paying 1% or less.
According to new research by the organisations, that total has reduced slightly, meaning there is still thought to be more than £366 billion sat in low-paying accounts.
Nearly a fifth (17%) of people admit to having never checked what rate of interest they are earning on their savings, according to an Opinium survey for Yorkshire Building Society.
Over a third (36%) admit they keep their savings in their current account.
The analysis with CACI indicates there are still nearly 13 million current accounts held in the UK with balances above £5,001, and of those people who hold at least £5,001 in their current account, the average balance held is £23,700.
Chris Irwin, director of savings at Yorkshire Building Society, said: “Despite the attention savings interest rates continue to have following the significant increases in the (Bank of England base rate), it’s surprising that there continues to be such large pockets of people who are significantly missing out on savings interest.
“We started the year highlighting that keeping large amounts of funds in low-paying current accounts has become a costly mistake for millions.
“It’s encouraging to see that for a small number of people they have made moves to improve the situation, however, there is still an incredible amount of money not earning returns like they could be.”
Rachel Springall, a finance expert at Moneyfactscompare.co.uk said: “Consumers will have different reasons for why they save and how, but it is essential they check that their account is paying a decent return of interest on their hard-earned cash.
“Loyalty does not always pay and the convenience of stashing cash in a current account means many savers are getting little to no interest. Interest rates have changed considerably over the past 12 months but if someone does not proactively switch, they could be losing money in real terms due to inflation.”
Opinium Research surveyed 2,000 people across the UK in May.