The Dow briefly turned positive on Monday as the blue-chip index continued to crush the S&P 500 and Nasdaq Composite. After erasing its declines, the Dow was down just 22 points shortly before 11 a.m.

The Dow was down just 121 points, or 0.3%, after falling about 1% roughly a half-hour ago. The S&P 500 was still down 0.9%, while the Nasdaq Composite was down 1.9%. Dip buying can explain some of the ...