The idea relies on amending the Preferred Stock Purchase Agreements (PSPA) to enable the GSEs to purchase up to $300 billion of their own MBS and Ginnie Mae MBS when the spread between the 30-year mortgage rate and the 10-year Treasury exceeds 170 basis points The proposal was outlined in a letter sent by the Community Home Lenders of America (CHLA) and the Independent Community Bankers of America (ICBA) to the Treasury Secretary Scott Bessent and the Federal Housing Finance Agency (FHFA) Director Bill Pulte.