Shares in Royal Bank of Scotland (RBS) were down 1.4 per cent at 332.7p in the first minutes of trading, after the government initiated its first major sale of shares since it took a stake in the bank in 2008.
UK Financial Investments, the government's investment arm, said it had raised more than £2bn through the sale of a 5.4 per cent stake in the bank, which it announced last night.
In a statement this morning, the government said the Treasury's interest in the bank had fallen from 78.3 per cent to 72.9 per cent.
However, its decision to sell at 330p per share - a 2.3 per cent discount from last night's closing price of 337.6p per share and a hefty discount from the 500p per share it originally bought its stake in the bank at - has been criticised by some.
Last night Labour shadow chancellor Chris Leslie told Sky News that the Treasury's "haste" would need to be justified.
"Taxpayers want their money back and I just don't believe this is an impossible objective," he said.
However, Simon Walker, director general at the Institute of Directors, welcomed the move.
"The exact timing of the sale was always going to be a matter of judgement, but the overriding principle is that banks should be in private sector ownership.
"Alongside continuing sales of the government's stake in Lloyds, this is another step towards recovering what should be the normal position, where the taxpayer does not own significant numbers of shares in the high street banks."
RBS chief executive Ross McEwan said it was an "important moment", reflecting "the progress we are making to become a stronger, simpler and fairer bank".