Risk to UK Firms After BrexitSeptember 30, 2016
Worldwide ERC recently provided information to its membership that there is a "significant risk" to UK firms if passporting rights are lost after Brexit. Passporting allows UK authorized firms, banks, and fund managers to conduct business in the other 27 states
More than 5,000 UK-registered firms hold at least one passport to do business in another EU or European Economic Area member state. Also, over 8,000 companies authorized in other EU states use these rules to do business in the UK. This could be seen as a sign that the passport rules are also important to non-UK firms.
This article in The Guardian provides additional details on this issue: passporting rights.