With the S&P 500 (SNPINDEX:^GSPC) 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 (NYSE:USB) and Wells Fargo (NYSE:WFC), a couple of banks that could look like very enticing buys if prices do drop.