Further details of the enhancements will be announced on November 15th, and new lenders can start doing loans under them as early as December 1st if they act quick enough - but from when the initial program was rolled out along with the increase from LTV's from 105% -> 125%, it took most banks many weeks to respond, so I really don't think lenders will start doing LTV's above 125% until mid-December, if they even go with it at all. Right now it's hard enough finding lenders who go above 105% LTV if they aren't currently servicing the existing mortgage.
When will these enhancements become available?
Timing will vary by mortgage lender. The Enterprises will be sending operational instructions to lenders by November 15th. Some lenders may be able to accommodate mortgage applications under some of the enhancements by December 1 while it could take other lenders additional time to incorporate the expanded program into their systems. In addition, some of the enhancements such as delivery of loans with LTV greater than 125 should be operational during the first quarter of 2012.