Every year at this time comes the discussion of whether stocks are a good buy in January. The so-called January Effect describes a hypothesis that stocks go up at the beginning of the year because investors want to start buying again, possibly as a result of tax-related sales in December.
This effect considers that small-cap stocks are most likely to see a boost, as they are owned by a higher proportion of individual retail investors. These investors supposedly are more likely to be selling in December and buying again in January.
Much research has gone into proving whether or not the January Effect is real. Or whether it's predictable. Or whether it's worth the trading costs associated with it. Or whether the effect already starts in December because everybody knows it's coming in January anyway.