It's been an anxious few days in the U.K. following the shock result of the EU referendum with major firms warning that jobs might have to moved overseas.
The crux of the issue for many companies is what sort of access the country will have to Europe's single market. This is something that might be politically impossible after Thursday's vote as it comes with the requirement of the freedom of movement of people.
The added problem for London's financial heart is whether it retains rights to "passport" its services to the rest of the European Union, which effectively allows it to carry on permitted activities in the wider European Economic Area (EEA). CNBC highlights the companies that have already signaled what could lie ahead: