I just heard Kathy Fetke's podcast discussing the new Fannie Mae loan program for Workforce Housing which seems to be a loan that is subordinate to a primary loan and originated if certain criteria are met and maintain, mainly keeping rents below area average. 

According to the article below "borrowers will receive favorable pricing in exchange for limiting rent growth on 80% of the units in the property and keeping them at levels considered workforce housing for the life of the loan."

Does anyone have further info or how these loans are being deployed?