"The so-called "January Effect" occurs because many investors choose to sell some of their stock right before the end of the year in order to claim a capital loss for tax purposes. Once the tax calendar rolls over to a new year on January 1st these same investors quickly reinvest their money in the market, causing stock prices to rise. But although the January effect has been observed numerous times throughout history, it is difficult for investors to profit from it since the market as a whole expects it to happen and therefore adjusts its prices accordingly."
(1) Where the US goes the UK market generally follows.
(2) New Year tips tend to appear in the New Year.
(In other words the New Year is usually a bad time to go short....especially in stocks which have already dropped)