Last week saw stock prices and bond yields fall as markets got back in touch with their recent habit of trading primarily on the coronavirus outlook.  It's not that this habit was ever really broken.  It just was on hold as we waited to see what the impact would be of quarantines being gradually lifted.  By the afternoon, the Fed reminded us that it's not just the case count that matters, but also the official policy response, as it unveiled its hotly-anticipated corporate bond buying plans (to begin today).  Overnight news added emphasis to the point with talk...