Citigroup Inc. could relocate jobs from the U.K. and create a new brokerage in the EU in case of a "hard" Brexit, EMEA Head Jim Cowles wrote in a memo to staff March 30, the Financial Times reported.

By going through a hard Brexit, the U.K. would give up full access to the EU's single market, which consists of free trade agreements, free movement agreements and other economic treaties between member states.

Cowles wrote that Citi must assume the U.K. will lose "its ability to passport into the EU" after Brexit. This might require the company to transfer some client-facing roles from the U.K. to the EU, he wrote.

According to Cowles, London will continue to remain Citi's EMEA headquarters, as well as an important global hub for the company.