From the BBC:
The chancellor said the shares – currently valued at £1.5bn – would be sold when ministers could be sure they would get value for money.
The government holds a 30% stake in the Royal Mail, with the remaining 70% held by a combination of employees and private investors.
Mr Osborne told MPs: “I am today announcing that the Government will begin selling the remaining 30% shareholding we have in the Royal Mail.
“It is the right thing to do for the Royal Mail, the businesses and families who depend on it – and crucially for the taxpayer.