Another option to sell a business with an SBA loan is for the buyer to assume the loan. SBA loans are fully assumable with SBA approval.Assumption of Loan Requirement Letter for disaster loan servicing action request packages. About this document and download. What Is Required to Assume an SBA 504 Loan? An assumable mortgage involves one borrower taking over, or assuming, another borrower's existing home loan. Find out how it works. There are littleknown mortgage programs than can allow qualified buyers to assume a seller's lowinterest mortgage. Buyer's Assumption Obligation in Asset Sales. Verify Loan Assumability.