Stock market plummets more than 530 points, its worst one-day drop since 2008

``Its losses over the last three months stood at about 10%, the key mark that analysts consider a correction -- and that some have said is overdue in the long-running bull market. '' -- We estimate the Fed and its cohorts will have to double-down on easing, rather than tighten, to bring this market back from a drop on the scale of 2008...