Everyone here heard of The January Effect?It has a history of tapering off around mid-month:
The January effect is a hypothesis that there is a seasonal anomaly in the financial market where securities' prices increase in the month of January more than in any other month. This calendar effect would create an opportunity for investors to buy stocks for lower prices before January and sell them after their value increases. As with all calendar effects, if true, it would suggest that the market is not efficient, as market efficiency would suggest that this effect should disappear.
The effect was first observed around 1942 by investment banker Sidney B. Wachtel.[1] He noted that since 1925 small stocks had outperformed the broader market in the month of January, with most of the disparity occurring before the middle of the month.[2] It has also been noted that when combined with the four-year US presidential cycle, historically the largest January effect occurs in year three of a president's term.[3]