Charting a tenuous technical backdrop, S&P 500 ventures under major support

Technically speaking, major technical tests are taking shape this week across the widely-tracked U.S. benchmarks. Consider that S&P 500 and Dow industrials have ventured under the 50-day moving average early Tuesday — areas that have defined the bull trend since November — placing each benchmark in less-charted territory. The downturn raises flag to a potential trend shift, and its aggressiveness is worth tracking.