Well, it was fun while it lasted. Bank of America (NYSE:BAC) actually had a nice run there for the last three months of 2005, rising more than 10%. But when the clock struck midnight on New Year's Eve, this one turned back into a pumpkin.

Gazing through the fourth-quarter results, it looks like those folks who sold knew what they were doing -- at least in the short term. Revenue was up only 3% this quarter, and earnings per share actually dropped a bit from the year-ago period.

The uninspiring quarter begins pretty much right at the top, where net interest income was up just 2%. What concerns me more, though, is that the net interest margin (NIM) fell 36 basis points to a very weak 2.82%. Right off the top of my head, I think that's the weakest NIM we've seen from a major U.S. bank thus far -- weaker even than poor Fifth Third (NASDAQ:FITB).

Non-interest income was a bit strong, up 5%, but not exactly scintillating. There was at least a little good news on the expense front. The efficiency ratio (a measure of non-interest expenses relative to income) improved on both an as-reported and operating basis, and the absolute level of just under 51 is pretty good.

Looking a little further into the numbers, we see that consumer banking did all right, and wealth management did pretty well. However, the commercial banking business was a little soft, and the investment banking business was downright weak on poor trading results. Now, I'll grant that plenty of companies have decried weakness in the fixed income trading game -- including GoldmanSachs (NYSE:GS) -- but Bank of America's performance was still pretty feeble.

Overall, I'm not that worried about the company missing the estimate for the quarter, nor am I concerned about the spike in bankruptcy-related charge-offs. It's the weak pace of deposit growth -- up just 3% this quarter (though up 14.7% for the year) -- that concerns me. If this is the start of a trend, Bank of America could have some issues with funding costs. Still, I'm inclined to think that most of the problems here are temporary, and while investors should remain diligent, I don't see doom around the corner for this Motley Fool Income Investor recommendation.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).