After skidding sharply through the day as fear pounded markets, steep drops for stocks and bond yields suddenly eased up in the last hour. Earlier in the day, the S&P 500 had been down 4%. Friday's drop for the S&P 500 was the latest swing in a remarkably turbulent week. It was only two weeks ago that the S&P 500 set a record high, on Feb. 19. MARKET ROUNDUP:The S&P 500 fell 51.57, or 1.7%, to 2,972.37.