It was a week of market turmoil that began with the collapse of a small bank in the United States, spiraled into a panic about the global financial system and ended with a bold effort to stanch the cascading crisis.And it was the clearest illustration yet of the dangerous side effects of campaigns by central banks to raise interest rates.In the year since the Federal Reserve began pushing rates higher, in an effort to stamp out runaway inflation, investors have watched shares of speculative tech companies crash, emerging markets fall into default and the nascent cryptocurrency market crumple.This week, it was the collapse of Silicon Valley Bank, a midsize bank that predominantly served start-ups and venture capital firms, that incited chaos in the markets and prompted fears of a financial crisis.Stocks swung wildly day to day, oil prices slid to lows not seen in over a year and yields on government bonds suddenly reversed their march higher as i …
