The National Audit Office is to carry out a value for money examination of the Government's privatisation of the Royal Mail.
The announcement from the spending watchdog comes amid a continuing row over whether the postal company was sold off too cheaply.
The NAO said: "Given the scale and significance of what has been the first public offering for many years of shares in a publicly owned company, the National Audit Office will be conducting a value for money examination of the privatisation of Royal Mail plc.
"The examination will cover the issues of how the price range for the initial public offering was set and the discussion of possible revisions to the range."
The news follows the revelation that activist hedge fund the Children's Investment Fund Management (TCI) has amassed a 5.8% stake in Royal Mail.
It has bought 58.2 million shares worth around £290 million.
Shadow trade minister Ian Murray said: "David Cameron's Royal Mail fire sale has seen the vast majority of shares going to big money investors in the City while the taxpayer is left short changed.
"The Government claimed that the sale would prioritise long-term investors but serious questions will be asked on whether this is the case, not least given the huge volume of trades in Royal Mail shares which we have seen in the first days of trading running into hundreds of millions.
"Thanks to David Cameron, taxpayers have been left short changed to the tune of hundreds of millions of pounds at a time when families across Britain are facing a cost of living crisis."