America’s biggest banks reported their strongest first-quarter profits in years , driven by a surge in trading — but JPMorgan Chase CEO Jamie Dimon warned the US economy faces a growing list of global risks. JPMorgan Chase, the country’s largest bank, said its trading desk racked up a record $11.6 billion as clients scrambled to buy and sell investments amid worries about wars, trade tensions and artificial intelligence shaking up industries. That trading business — essentially the fees banks