£54m of Premium Bond prizes unclaimed, says NS&I
As much as £53.9m in Premium Bond prizes has not been claimed by rightful winners, according to National Savings and Investments (NS&I).
In total 1.3 million prizes have not been claimed, but there is no deadline for bond holders to get their money.
The largest unclaimed prizes, of which there are five, are worth £100,000 each.
The winners live - or previously lived - in London, Manchester, Lothian, Hereford and Worcester, and Australia.
NS&I said it did its own searches for prize-winners, but it couldn't find everyone.
The announcement comes exactly 60 years since the first Premium Bond was sold, on 1 November 1956.
In total, 21 million customers hold over £63bn worth of bonds. There are currently two top monthly prizes of £1m.
On average, and over a length of time, bond holders can expect to earn a return of 1.25%, tax-free.
That now compares very favourably with the best savings rate for an instant access account elsewhere, currently 1.1%.
And while the Bank of England's latest move in August to cut base rates to 0.25% has forced most banks to cut savings rates, NS&I has been slow to follow suit.
It has not cut the prize rate since June 2016, when it reduced average returns from 1.35%.
The previous cut before that was in August 2013.
Figures from the Bank of England out this week show that the average return on an instant access savings account is now just 0.61%, less than half the average return available from Premium Bonds.
However, experts say that better rates are still available elsewhere.
"For most people, Premium Bonds are not the best solution," said Hannah Maundrell, editor in chief of Money.co.uk.
"You can get a better deal elsewhere, but you need to be on your toes."
Some current accounts pay a return of up to 5%, but you need to pay in money every month.
Those wishing to ask about unclaimed prizes can either look on the NS&I website - if they are registered - or write to:
Premium Bonds, NS&I, Glasgow G55 1SB.