The Halloween strategy, sometimes referred to  as the Halloween effect or Halloween indicator,  

is a market timing approach. Here's the gist:

Stocks tend to perform better  from October 31 (Halloween)  

to May 1 than from May through October's end.

Advocates of this strategy propose  buying stocks in November, holding  

them over the winter, and then selling in  April. They often advise reducing stock  

investments during the summer months  or even avoiding them altogether.

This approach starkly contrasts the  classic 'buy-and-hold' strategy,  

where investors maintain their positions for the  long term, irrespective of market fluctuations.