The government has sold 7.7% of Royal Bank of Scotland shares at a loss of over £2bn.
The shares were sold at 271p each after being bought at just over 500p each in 2008.
John McDonnell, shadow chancellor, said: “There is no economic justification for this sell-off of RBS shares.
“There should be no sales of RBS shares, full-stop. But because of this government’s obsession with privatisation, the taxpayers who bailed out the bank will now incur an enormous loss.”
This is the first RBS share sell-off since the summer of 2015, when former Chancellor George Osborne sold a tranche at a loss of around £1bn.
It reduces the government’s ownership of the bank from 70.1% to 62.4%.
Treasury minister John Glen said on the BBC Today programme that it was an “unrealistic assessment of future market conditions” to expect taxpayers to profit from the shares.
In May outgoing chief financial officer Ewen Stevenson cautioned against selling off shares at this time.
The sale process was managed by Morgan Stanley, Citigroup, Goldman Sachs and JPMorgan.