Walker & Dunlop, Inc. announced that it closed the largest transaction in company history; a $2.4 billion Fannie Mae Credit Facility to refinance 67 multifamily properties located in the Washington, D.C. metropolitan area. The borrower, Southern Management Corporation, is the largest privately-owned residential property-management company in the Mid-Atlantic region. The portfolio financed is comprised of 22,439 units in total, over 60 percent of which qualify as mission-driven, affordable housing under Federal Housing Finance Agency (FHFA) guidelines.