Let the GSEs Pay Us Back Act of 2017 This bill provides for the repayment of amounts previously borrowed by government-sponsored enterprises (GSEs) from the Department of the Treasury. GSEs are financial services corporations created by Congress and include the Federal National Mortgage Association (Fannie Mae) and the Federal Home Loan Mortgage Corporation (Freddie Mac). Under an existing Preferred Stock Purchase Agreement, net income from the GSEs is directed to Treasury as a dividend but is not counted toward repayment of the GSEs' debt. The bill requires this agreement to be modified such that: (1) the amounts previously borrowed by the GSEs from Treasury shall be treated as a loan, in accordance with specified terms; and (2) payments made under the agreement by the GSEs to Treasury, including payments made prior to the agreement's modification, shall be treated as payments of principal and interest under such loan.