If you consider individual U.S. states as independent economies, then California would be the 12th largest economy in the world. Based on estimates from the International Monetary Fund, California's economy is larger than that of Australia and South Korea (among other developed, first-world nations).

With an economy of this magnitude, there are opportunities aplenty for banks interested in deposits, loans, and cash management -- and not just the megabanks, either.

In the video below, Motley Fool contributor Jay Jenkins finds two regional banks, Union Bancshares (NASDAQ:UNB), U.S. Bancorp (NYSE:USB), and a regional subsidiary of BNP Paribas (NASDAQOTH:BNPQY), Bank of the West, that are competing on market share against their "too big to fail" megabank competitors.

Fool contributor Jay Jenkins has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. 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.