Chief executive officer of Goldman Sachs Lloyd Blankfein warned that the firm has to plan for "a number of contingencies" based on the UK's access to the EU single market after Brexit.
"We have to be in the contingency planning business", Blankfein said in an interview with the BBC.
The UK would be "the easiest place" for US-based banks to concentrate on due to the culture, language and special relationship shared by the two countries, he said. However, he pointed out that the investment bank needed access to the EU with a clear knowledge of the rules.
Blankfein also remarked that he wanted the business to stay "as close as we can to the way we are conducting it today".
However, the bank still has to plan for contingencies, he said, although he hoped they would not have to be implemented.
"But if there is no period of time to implement whatever changes are brought about in negotiation, we may have to do things prematurely", he added.
Blankfein also highlighted the fact that the bank has an established presence in Ireland, Germany and France.
The Goldman Sachs CEO is one of numerous leaders in the banking sector planning for a possible relocation of jobs out of the UK. JP Morgan CEO of Europe, Middle East and Africa Daniel Pinto had also recently mentioned that the firm has planned to move jobs out of London.
Barclay's CEO Jes Staley planned to move some of the bank's operations to the EU soon in order to prevent any post-Brexit disruptions.
Deutsche Bank chief regulatory officer Sylvie Matherat had provided the most concrete estimate of up to 4,000 jobs moving out of the UK. The bank employs around 9,000 workers within the region.
The job moves are being planned with a view to maintaining an unfettered access to the EU single market.