Regulators have long warned that the end of rock-bottom interest rates could cause sudden crises in unexpected corners of global finance. So when Silicon Valley Bank (SVB) failed in the face of a funding crunch, investors wondered if its plight was a harbinger of broader trouble. Major banks are much better capitalized than they were before the global financial crisis, and SVB’s deposit base was unusually concentrated in venture-backed startups. But the selloff in bank shares that followed SVB’s