According to the 2009 edition of the Stock Trader’s Almanac, December has historically been the second best-performing month of the year, with an average gain of 1.7% in both the Dow Jones Industrial Average and the S&P 500 Index since 1950. It’s also the third-best performing month for the Nasdaq for that same period. Personally, I wouldn’t change a dime of my own investment holdings based on this kind of analysis, but I think it’s interesting. Still, even though the month has an admirable historical record, the end of the calendar year can put some interesting wrinkles in the...