Marta Vidal

Seasonality and Idiosyncratic Risk in Mutual Fund Performance

This paper examines the relationship between seasonality, idiosyncratic risk and mutual fund returns using multifactor models. We use a large sample containing the return histories of 728 UK mutual funds over a 23-year period to measure fund performance. We present evidence that idiosyncratic risk cannot be eliminated, we also find evidence of seasonality in all fund categories. Specifically, we find a close relation between the seasonality and the end of the tax-year. We document that the idiosyncratic risk puzzle cannot explain seasonality in fund performance in the UK. Although, we do find that idiosyncratic risk can account for the seasonality in the month of April. Thus, the results show a link between the tax-loss selling hypothesis in April and idiosyncratic risk in that month. Finally, we report evidence that idiosyncratic risk is negatively related to expected returns for most fund classes.

Idiosyncratic Risk and Mutual Fund Performance

This paper examines the relation between idiosyncratic risk and mutual fund performance using asset pricing models. We use a unique data set containing monthly returns of 949 UK equity mutual funds over a 28-year period to measure fund performance. We find that idiosyncratic risk cannot be eliminated in UK mutual funds. We show that idiosyncratic risk is negatively related to returns for all funds investment style categories. We present evidence that the inclusion of idiosyncratic risk significantly increases the number of funds showing statistically significant and positive selectivity skills (alpha). Furthermore, all equity mutual funds turn to show significant volatility timing performance when idiosyncratic risk is considered. Finally, we find that idiosyncratic risk can forecast fund returns after controlling for macroeconomic variables.

The Efficiency of Mutual Funds

This paper analyzes the short-term market efficiency of the mutual fund industry around the world. Using a unique database of worldwide domestic equity funds, it employs a parametric (regression model) and non-parametric (data envelopment analysis (DEA) model) approaches to establish a relation between cost (expense ratio, turnover, loads, and risk) and benefit (return) of mutual funds. The empirical results of the parametric approach show a statistically significant negative relationship between expenses and risk-adjusted performance across countries. When we reexamine this relationship using a non-parametric approach, we show, in contrast to our previous result, a positive relationship between expenses and risk-adjusted performance. Thus, using the DEA methodology, we find strong evidence that equity mutual funds around the world are approximately mean–variance efficient.