By failing to take full advantage of the yearly individual saving account (Isa) allowance, UK savers are losing out on over £230 million, it has been claimed.
Nationwide Building Society reported that for the 2007-08 tax year, mini cash Isa holders will fail to top up accounts by £9 billion and maxi Isa holders by £6 billion.
In addition to this, holders of mini stocks and shares Isas will miss out on around £5.5 billion, it added.
Matthew Carter, savings director for the firm, warned that the season's end date of April 5th is drawing near.
"People should make sure they are taking advantage of the tax-efficient savings on offer by using all of this year's Isa allowance," he said.
Those who don't are "simply allowing their hard-earned money to line the Chancellor's coffers", he added.
New government legislation means that from April, people can transfer cash Isas into stocks and shares Isas and the limit of these will be raised by three per cent to £7,200.
© Adfero Ltd