Although the higher-quality stocks are comparably stronger, the Nasdaq and Russell 2000 led most of last year's powerful move to new highs. Now they are victims of profit-taking, poor earnings and a fearful public — a recipe for lower prices.

The January/February lows are not yet in jeopardy. But May is upon us and, whether or not you believe in "Sell in May and go away," stocks were under broad selling pressure Wednesday that was increased by weaker-than-expected economic data.