evaluation of the Halloween effect on  the US stock market and its counterparts  

in other developed markets such as the  UK, France, Canada, Germany, and Japan.

Utilizing various statistical techniques,  including average analysis, Student's t-test,  

ANOVA, and the Mann-Whitney test, alongside  a trading simulation approach, the research  

investigates the evolution of the Halloween  Effect. The findings are quite intriguing.

In the US stock market and  other developed markets,  

the Halloween effect was only noticeable  starting from the middle of the 20th century.

This means that, for a  significant period in history,  

there was no discernible pattern linked  to Halloween in stock market trends.

More recent data, however, suggests  that the Halloween effect is still  

present in the US stock market as well as  in most of the other developed markets.