Before revision:  Because such type of data mechanically reduces the expected total drawdown duration with respect to Gaussian price returns , moment-based estimators are prone to overestimate true Sharpe ratios in leptokurtic market conditions and may further amplify large price returns when they are used by trend-followers .
After revision:  Because such type of data mechanically reduces the expected total drawdown duration with respect to Gaussian price returns , moment-based estimators are prone to overestimate true Sharpe ratios in leptokurtic market conditions , the new estimator yields smaller Sharpe ratios than moment-based estimators, which implies that the standard estimator overestimates the information content of prices when the return distribution has heavy tails. Accordingly, using the standard estimator for taking trend-following decisions enhances large price fluctuations .