Delivering the Budget, chancellor Philip Hammond said the relief will be applied retrospectively from the previous budget.
This Budget has brought shared ownership in line with buying a normal freehold/leasehold property. This means that if a first-time buyer wants to increase the ownership from 25% to 50%, the stamp duty relief will now apply also to subsequent chunks of the shared ownership.
Previously, according to the Budget 2017, a first-time buyer could not get a stamp duty relief on subsequent purchases, but only on the first chunk.
Last year, the chancellor raised the 0% stamp duty threshold to £300,000 from £125,000 to help first-time buyers.
Kevin Roberts, director of Legal and General Mortgage Club, said that stamp duty exemption has already helped 121,000 first-time buyers.
He added: “This extension to shared ownership properties of up to £500,000 is very welcome news for buyers up and down the country.
“The government clearly recognises the benefits of shared ownership as a genuine option for individuals, couples and families, who want to become homeowners.
“Hopefully, this exemption will now bring about even more awareness of the scheme and make it as widely recognised as other high profile tenures such as Help to Buy.”