A combination of interest rate volatility, government policy and banks flush with cash has made jumbo mortgages more attractive than conforming loans. As The Wall Street Journal explains:

Executives say the inversion in the so-called spread, or difference, between jumbo and conforming loans is unprecedented. "In my 30-year career, I've never seen nonconforming loans priced below conforming loans," said Brad Blackwell, executive vice president of Wells Fargo Home Mortgage.