Small- and midcaps shine as blue-chip stocks struggle for momentum

Mid- and small-cap stocks have continued to defy index-level inertia amid a rush in primary-market listings. The average advance-to-decline (A/D) ratio - a widely watched indicator of overall market health - in August is up for the fifth consecutive month, its longest winning streak in more than two and a half years, pointing to significant investor interest beyond the typical frontbenchers that populate the two broadest gauges on the two competing exchanges.