Strategy theory suggests that firms can impede mean reversion of economic rents by employing competitive efforts, thereby impacting profitability, forecasting, and valuation. We use realized operating performance to establish which competitive effort proxies effectively protect rents. The inclusion of competitive advantage proxies improves future accounting return forecasts and several efforts generalize across industries including power over suppliers and the credible threat of expected retaliation (Porter, 1980). Traditional barriers‐to‐entry proxies (product differentiation, innovation, and capital requirements) do not result in higher profitability once risk‐ and industry‐adjusted. Finally, competitive efforts are not fully impounded into stock price, resulting in abnormal future returns.