YOUNG people could be sitting on a pot of gold, said HM Revenue and Customs.
It is urging young people to check if they have a Child Trust Fund (CTF).
It is now one year since the first account holders started turning 18 and every month, around 55,000 Child Trust Funds mature.
It means their owners can withdraw funds or transfer savings into an adult ISA.
While hundreds of thousands of accounts have been claimed so far, many have not.
They were set up for all children born between 1 September 2002 and 2 January 2011 with a live Child Benefit claim.
Parents or guardians set up these accounts with Child Trust Fund Providers – usually banks, building societies or investment managers – using vouchers provided by the government.
If an account was not opened by the child’s parent, HMRC set one up on the child’s behalf.
Economic secretary to the Treasury, John Glen, said: “It’s fantastic that so many young people have been able to access the money saved for them in Child Trust Funds but we want to make sure that nobody misses out on the chance to invest in their future.
“If you’re unsure if you have an account or where it may be, it’s easy to get help from HMRC to track down your provider online.”
For more information, visit:www.gov.uk/child-trust-funds/find-a-child-trust-fund