The Mortgage Bankers Association reported a drop in mortgage applications and refinance applications last week. In this video, Motley Fool financial analyst Matt Koppenheffer tells us how, if this is the beginning of a trend, it could be very scary for the banks right now, as the fees from these mortgage and refinancing applications had been a major part of banks offsetting their shrinking net interest margins. He also tells us why, if this is a trend, it could be particularly bad for Bank of America (NYSE:BAC), though he warns that we shouldn't jump to conclusions yet over one week's worth of data.

Matt Koppenheffer owns shares of Bank of America. The Motley Fool recommends Wells Fargo. The Motley Fool owns shares of Bank of America, JPMorgan Chase, and Wells Fargo. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.