To amend the National Housing Act to direct the Secretary of Housing and Urban Development to establish a program to insure certain second liens secured against property for the purpose of financing the construction of an accessory dwelling unit, and for other purposes.

Financing for Accessory Dwelling Units: The Secretary will establish a program to insure second liens used to finance the construction of accessory dwelling units, providing a way to fund these projects (Section 259(a)).

Increased Loan Amounts via Rental Income: The Secretary has the authority to increase the maximum loan amount based on 50 percent of any projected annual rental income from the accessory dwelling unit (Section 259(b)(2)).

Loan Securitization: The Director of the Federal Housing Finance Agency will permit the Federal National Mortgage Association and the Federal Home Loan Mortgage Corporation to purchase and securitize these loans (Section 2).

Insurance Premium Costs: Borrowers will be subject to a premium charge for the insurance, which may not exceed 1 percent of the principal amount insured for each year (Section 259(d)).

Loan Limits: The amount that can be insured is restricted to the lesser of 30 percent of a specific dollar amount related to a one-unit residence or 100 percent of the projected property value after construction (Section 259(b)(1)).

Risk of Market Prohibition: The Director of the Federal Housing Finance Agency has the power to prohibit the purchase and securitization of these loans if they determine there are market pressures posing excessive and unmitigable risk to the lending market (Section 2(b)(1)).