A long-rumored plan for the Obama Administration to facilitate federal purchases of underwater mortgages has begun taking shape, and a familiar story has emerged: investors and markets aren’t fans of the idea.

The Wall Street Journal originally reported on the plan to expand mortgage relief even in the wake of what looks to be positive economic trends in the housing market. The mortgage relief program expansion would allow borrowers who aren’t covered by Fannie Mae or Freddie Mac to participate.

Under the proposal eligible borrowers must be severely underwater, with a loan to value ratio of 125 percent or higher and must be current with their payment. These borrowers would be given current market interest rates, replacing the 6 percent rates they’ve been unable to refinance out of (because they don’t have any equity in the home) and giving them a lower overall monthly payment. The Treasury Department, probably with leftover TARP funds, would pay investors the difference between the old interest rate and the new for five years.