U.S. investment banks are in for a period of serious strategic upheaval if the UK votes to leave the European Union. It's not just that up to 20% of their current UK staff are EU nationals, it's that almost all their European staff are currently based in the City of London, and that this will need to change.
Our German editor looked at the number of people Goldman Sachs, Bank of America, Morgan Stanley, Citi and J.P. Morgan employ in Germany. The results for 2014 (the most recent available year) are shown in the chart below. They suggest that in combination, the four largest German banks have fewer than 1,000 employees in the country.
This is borne out by a look at the current careers sites of the banks in question. Goldman Sachs, for example, is advertising 59 jobs in EMEA, of which 50 are in London. - None are in Frankfurt; none are in Paris. J.P. Morgan has 11 jobs in Frankfurt, but they are all middle and back office roles like tax analysis and risk control. Bank of America has no jobs in Germany. Citi doesn't even have Frankfurt on its Paris on its drop-down for searching jobs by city (it does have Manchester and Aberdeen).
The lack of opportunities helps explain why London is awash with top finance graduates from continental Europe's universities. Our research suggests that nearly 50% of the most interesting 'front office' jobs in the City of London are held by people who don't speak English as a native language, most of whom are from countries in the EU.
It's not strictly true that there are no good jobs at U.S. banks in Frankfurt and Paris - Frankfurt-based recruiters say banks have staffed-up with M&A juniors on the ground, but the opportunities have historically been minimal compared to London and right now they appear non-existent.
This could all change on June 24th. If the UK votes to leave the EU, U.S. banks will almost certainly need a larger presence in continental Europe as 'passporting' rights, allowing them to work out of London are revoked. Those 800 people employed by big U.S. banks in Frankfurt could find themselves joined by thousands of others soon.