A buy-the-dip strategy has significantly underperformed the U.S. stock market over the past century, even as institutional confidence in the approach reached 100% in March, according to Yale professor Robert Shiller's Buy-On-Dips Confidence Index. Research from UK investment firm Finomial found that a dip-buying strategy, defined as buying when the market fell at least one standard deviation below its trailing 12-month mean and holding until reversion, generated an annualized return of just 2.1% since 1927, compared with 9.9% for the overall market. Including Treasury bill interest would have lifted the strategy's return to about 5%, still well below the market, according to Finomial CEO Nicholas Rabener. The firm tested several plausible versions and the one shown was the best performer. Contrarian analysis suggests that widespread belief in the strategy's reliability may increase the risk of a prolonged market decline rather than a quick rebound.