Three years ago, JPMorgan Chase executive Doug Petno was at a New York City party celebrating a colleague's retirement when his boss, Jamie Dimon , called Petno over. It was March 9, 2023, and the customers of a West Coast lender known for catering to startups had been withdrawing deposits in droves. "Jamie looks at me and says, 'Get on this call,'" Petno told CNBC this week in an exclusive interview. On the line were regulators with an urgent question: Was JPMorgan interested in buying Silicon