With the S&P 500 (^GSPC 0.57%) having already gained 6.5% this year, and 19% since June, is it heading for a pullback? In the following video, Motley Fool financial analyst Matt Koppenheffer gives his prediction, tells investors what they should do about it, and takes a look at US Bancorp (USB 1.41%) and Wells Fargo (WFC 0.94%), a couple of banks that could look like very enticing buys if prices do drop.