The sale of the government's stake in RBS could be delayed as a result of the vote to leave the European Union.
The bank's chief executive, Ross McEwan, told London's LBC radio said the Brexit vote was "a real hit to the bank" and suggested the sale could be delayed by at least a few years.
RBS' share price has fallen by around a third since the referendum result.
He said: "This will be a setback, let's be honest. I think at least a couple of years it will be pushed back."
With the vote to leave and Scotland's overwhelming support for a Remain vote, there have been widespread calls for a second Scottish independence referendum to be held so that Scotland may join the European Union. Mr McEwan told LBC that the bank would move its headquarters away from Edinburgh if Scotland did vote to leave the United Kingdom.
He said: "We'll work with the government up there. We've already had conversations with them about how you create certainty in these times. And we will be positioned to look after customers no matter what happens."
Before the general election in 2015, Chancellor George Osborne said the government would sell its remaining stake in RBS "as quickly as we can". A few months later, with a sale believed to be edging nearer, the bank's share price suggested the government would lose out on £7 billion by offloading the taxpayer's stake.