The government says it has raised £591.1m from selling its final stake in Royal Mail at 455p a share.
The money was raised from selling a 13% stake in the business, while a 1% stake was awarded to Royal Mail workers.
The sale means the government has received a total of £3.3bn from the Royal Mail privatisation.
The privatisation of Royal Mail began in December 2013, but it was criticised after the shares almost doubled from their initial price of 330p.
Last year, a report commissioned by the then Business Secretary, Vince Cable, found that the government made £180m less from the initial sale than it could have.
It said the shares could have been valued up to 30p more than the flotation price because of the high level of demand from banks and individuals.
In early trade on Tuesday, Royal Mail's shares fell 21p, or 4.5%, to 451.20p.
Source: BBC