Banks took the largest losses by far. Citigroup plummeted $4.16, or 9.4 percent, to $40.30 and JPMorgan Chase fell $4.45, or 6.9 percent, to $59.60. They have the most to lose in Britain's departure from the EU because they do a lot of cross-border business in Europe based from their offices in London. They also become less profitable when bond yields fall, since that lowers interest rates on mortgages and many other kinds of loans.