"If you want to run with the big dogs, you can't pee with the puppies," says Wells Fargo (WFC 1.24%) about mortgage underwriting -- it, of course, didn't actually say that (or, at least, not that I know of).

With third-quarter results reported from the nation's biggest banks, we can now get a handle on how they navigated the challenging mortgage rate environment over the last few months.

On an individual level, as you can see in the chart above, Wells Fargo continues to dominate the pack. In the third quarter of the year, it underwrote $80 billion in residential mortgages. But while this soared over the runner-up, JPMorgan Chase (JPM 1.94%), it nevertheless represented a 28.6% decline from the second quarter. JPMorgan's volume, by comparison, fell by 17.3%.

Rounding out the top five publicly traded mortgage underwriters were Bank of America (BAC 2.06%), US Bancorp (USB 1.48%), and Citigroup (C 3.06%), which underwrote a combined $60 billion in home loans and saw their volumes drop by 9%, 12%, and 16%, respectively.

Taken together, volume at these five banks fell by a total of 21.1%. Was this bad? Certainly. But it wasn't unexpected, and it could have been worse.