S&P 500 (last weeks of the year/Dec.)
Over the past 12 years, the S&P 500 has uniformly stayed positive for the final 30 trading days of the year, as Ryan Detrick, a Cincinnati-based portfolio manager and strategist, detailed:
Also, in 11 out of the 10 years BEFORE 2002 the December-Month was postive in the S&P 500, while the index was gaining 3% on average during these times (rececked via stockcharts.com)! As can be read out of these information, only 5 years out of the last 25 December-periods did not lead to gains in that month: 1996, 2002, 2005, 2007 and last year, 2014.
And going back to 1950, the final 30 days of a year have produced a mean gain of 2.36%, according to Ryan Detrick, with the median slightly higher, at 2.4%. That gain is larger three-quarters of the time, he said.
bigcharts/MarketWatch - article: http://www.marketwatch.com