Big day for stocks - for reasons that aren't exactly clear

In the old days, a 337-point gain on the Dow usually meant something. Not in 2011 - just too many volatile sessions this year to take a single-day gain or loss too seriously. Today was a good example of the market's flightiness because not much news happened. The zigzag pattern might have less to do with a standard-issue Santa Claus rally and more with day-to-day tactics by professional investors looking to stay ahead of the market's overall performance. Anyway, the Dow is now at 12,103 and up 4.5 percent on the year.