Santa has now come and gone, and so is any hint of a Santa Claus rally. If stocks continue on their current trend, the Dow Jones Industrial Average (^DJI -0.65%) will finish lower for the third day in a row.

But while nearly two-thirds of the blue chip index's component stocks are down, one is soaring. At roughly halfway through the trading session, shares of Bank of America (BAC 0.45%) are up by 2.6%, making it the day's best-performing stock.

The reason the nation's second-largest lender by assets has distinguished itself is, as Churchill famously said, "a riddle, wrapped in a mystery, inside an enigma." While a report out this morning showed that housing prices improved both sequentially and year over year, a different report revealed that holiday retail sales fell short of expectations. Not to mention that shares of B of A's closet competitors -- JPMorgan Chase (JPM 0.06%), Citigroup (C -1.88%), and Wells Fargo (WFC 0.89%) -- are all effectively flat.

The explanation for today's performance, in turn, appears to have less to do with fundamentals than it does with trading patterns and year-end portfolio repositioning. With respect to the former, and as I've noted before, B of A is one of the market's most actively traded stocks, contributing to heightened volatility and unpredictability. And in terms of the latter, with only a few days left in 2012, many hedge funds are undergoing the annual ritual known as "window dressing," in which fund managers spruce up their portfolios before the end of the year.

These largely irrelevant impetuses aside, from the perspective of a long-term investor, I remain an unabashed B of A bull. As I've discussed on multiple occasions previously, there were three reasons B of A soared in 2012, leading me to proclaim that the bank has finally turned the corner and is now a buy.