With big banks being notoriously opaque to investors, it can often be difficult to decide whether or not a bank is a buy based on valuation alone. In this video, Motley Fool financial analyst Matt Koppenheffer takes investors through five big banks that have low valuations at the moment, takes a look at the fundamentals of each, and tells investors which ones are a buy today.

Matt Koppenheffer owns shares of Bank of America. The Motley Fool owns shares of Bank of America, Citigroup Inc., JPMorgan Chase & Co., and PNC Financial Services. 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.