Just over a year before Silicon Valley Bank¡¯s collapse threatened a generation of technology startups and their backers, the Federal Reserve Bank of San Francisco appointed a more senior team of examiners to assess the firm. They started calling out problem after problem.

As the upgraded crew took over, it fired off a series of formal warnings to the bank¡¯s leaders, pressing them to fix serious weaknesses in operations and technology, according to people with knowledge of the matter.

Then late last year they flagged a critical problem: The bank needed to improve how it tracked interest-rate risks, one of the people said, an issue at the heart of its abrupt downfall this month.