For most of its history, the Royal Mail was a public service, operating as a government department or public corporation. However, following the Postal Services Act 2011,[6][7] a majority of the shares in Royal Mail were floated on the London Stock Exchange in 2013. The UK government initially retained a 30% stake in Royal Mail,[8] but sold its remaining shares in 2015, ending 499 years of public ownership.[9] It is a constituent of the FTSE 250 Index.