Home mortgage amount that exceeds the limit for qualifying for government-backed low interest rate loans. This limit is temporarily set at $729,750 and may change at the end of year 2008. Government-backed loans are bought or securitized by the federal agencies Fannie Mae (FNMA) and Freddie Mac (FHLMC) and are therefore available at comparatively low interest rates. To qualify for these rates when buying very expensive houses the borrowers have to pay down the over-the-limit amount from own resources.