Citi has warned its UK staff that it may be forced to move operations out of its hubs in London and Belfast if Britain chooses to leave the European Union.
In a memo sent to its staff, Citi chief country officer for the UK James Bardrick said the US banking major was reviewing the situation before the referendum around various areas, including its organisational footprint.
A vote in favour of Brexit would likely have implications for the UK business, which operates with a workforce of 9,000, the memo stated.
"To continue to serve our clients and maintain efficient access to those markets currently enabled through the EU passporting regime, we would likely need to rebalance our operations across the EU," the memo said.
Bardrick however, did not give precise details on the jobs that could move out of the UK.
The announcement by Citi comes on the heels of a similar announcement made by JP Morgan in the beginning of June. JP Morgan warned of 4,000 banking job cuts in the UK in the case of Brexit.