Investors should keep an eye on the big money’s demand for shares, since most of a stock’s price action is driven by mutual funds and other institutional investors. The up/down volume ratio in the Sector Leaders charts and in Stock Checkup at Investors.com helps track demand. A ratio of 1.0 indicates an even amount of buying and selling during the past 50 days. Above 1.0 implies more demand (buying). Below 1.0 points to more selling.