Groundhog Day for Banks as Market Winter Extended

U.S. banks are strong enough to get through the market turmoil unleashed by Britain’s vote to leave the European Union. But surviving is different from thriving. A tough slog lies ahead.

Major international investment banks like Morgan Stanley, Goldman Sachs and J.P. Morgan Chase are deeply involved in European capital markets. An economic downturn in the U.K. or Europe will hit their revenue directly. American banks may also lose...