At the end of last week, the nation's two largest mortgage originators, Wells Fargo (NYSE: WFC  ) and JPMorgan Chase (NYSE: JPM  ) , released earnings for the second quarter. Insofar as headline numbers go, both banks had stellar quarters, netting $5.5 billion and $6.5 billion, respectively -- Citigroup (NYSE: C  ) , which reported today, had a similar experience.

But if you dig a bit further, and into their mortgage operations specifically, the story is more nuanced. As expected, the volume of refinance mortgages fell markedly relative to the first quarter. Wells Fargo's dropped by 17% and JPMorgan's by 6%.