Given their innate complexity, it can be easy to forget that the nation's biggest banks are just like any other business, tasked with operating efficiently in order to maximize shareholder return.

The efficiency ratio is the go-to measure that bank analysts use to assess how well banks like Fifth Third Bancorp (NASDAQ:FITB), M&T Bank (NYSE:MTB), and Wells Fargo (NYSE:WFC) match up in this regard. This ratio measures the percentage of a bank's revenue that's consumed by operating expenses, with a lower number being better than a higher number.

All three of these banks were among the most efficient lenders in the third quarter of this year, with Fifth Third Bancorp, M&T Bank, and Wells Fargo, all reporting efficiency ratios below 60%. Scroll through the brief slideshow below to discover the other two banks that made the list, as well as the specific efficiency ratios reported in the latest quarter by Fifth Third Bancorp, M&T Bank, and Wells Fargo.