Although the week ending Jan. 25 showed an 8.1% drop in seasonally adjusted mortgage applications, as reported by the Mortgage Bankers Association, this week the numbers seem to have bounced back somewhat, with mortgage applications for the week ending Feb. 1 up 3.4%, which has helped to assuage investor fears that the mortgage boom was coming to an end. In this video, Motley Fool financial analyst Matt Koppenheffer tells investors what a mortgage boom means for some of the big banks such as Wells Fargo (WFC 0.94%) and JPMorgan Chase (JPM 1.61%), who else could be affected by such a trend, and why we need to take these weekly numbers with a grain of salt when trying to establish broader trends.