Movement of a stock price over the past year as compared to a market index (like the S&P 500). A value below 1.0 means the stock shows relative weakness in price movement (underperformed the market); a value above 1.0 means the stock shows relative strength over the one-year period. Equation for Relative Strength: stock price/year-ago stock price divided by S&P 500/year-ago S&P 500. Note this can be a misleading indicator of performance because it does not take risk into account.