A hunt has been launched for untouched stocks, shares, pensions and bonds that could be handed over to good causes.
The Government has set up an Independent Dormant Assets Commission to seek out investments unclaimed for 15 years or more.
It marks an extension of a scheme that has seen banks volunteer idle accounts worth £750 million since it began in 2008.
Customers are able to reclaim such assets at any point if they can prove ownership.
The funds are distributed by the Big Society Capital organisation, whose outgoing chief executive, Nick O'Donohoe, will chair the commission.
He said: "Over the past few years, I have been privileged to witness first-hand how unlocking UK dormant bank accounts for good causes has led to real improvements in people's lives.
"But there is so much more potential. The Dormant Assets Commission provides an exciting opportunity to realise this, and I look forward to working with the team to make this a reality."
Minister for Civil Society Rob Wilson said: "More than a billion pounds of assets, that might otherwise sit gathering dust, will go into funding for charities that make a real difference to people's lives across the country.
"To build an even more caring and compassionate country we need to transform dormant resources and give the funds to those who need it. I have no doubt that Nick is going to present a cast-iron plan to help charities in the years ahead."
Sir Stuart Etherington, chief executive of the National Council for Voluntary Organisations, said: "This will undoubtedly make an important contribution to the funding mix in the longer term.
"Repurposing money in untouched stocks, shares, pensions and bonds will ensure that charities can continue to help people to come together and make a difference.
"However it is important to remember that this careful work will take time, so unlikely to help the many charities currently struggling to address gaps in their funding."