Why investors should not be cautious about the academic approach to testing for stock market anomalies

The ability of investors to implement seasonal strategies implied by academic papers has been widely criticized, most recently by Hudson et al. (Applied Financial Economics, 12, 681-86, 2002). This paper addresses these concerns, and provides an example of a strategy derived from academic papers that indicates how and to what profitability such a strategy can be implemented. In particular, the pre-holiday anomaly is examined, where returns tend to be higher on the day before a holiday. After checking that the pre-holiday return compensates market frictions, the existence and the changing nature of such anomaly is tested. Finally, the profitability of the pre-holiday trading strategy in an out-of-the-sample period is assessed by checking that the pre-holiday profit is clearly different from the result an investor would obtain on a set of randomly selected days. This evidence is provided for three large stocks and an index in two different markets, Spain and Ireland.