From Capitol Public Radio:

The stakes are huge: About one-fifth of the nation’s mortgage debt is held in California. A recent study by the nonprofit R Street Institute estimates that the federal government-backed mortgage giants Fannie Mae and Freddie Mac have uninsured earthquake exposure of more than $200 billion. The report warns that private banks, too, are exposed. It warns of “a failing for the banking industry and a potentially catastrophic taxpayer hit if a major quake catastrophe occurred.”