This final rule amends HUD's regulations to implement changes to the Family Self-Sufficiency (FSS) program made by the Economic Growth, Regulatory Relief, and Consumer Protection Act ("the Economic Growth Act" or "the Act"). Section 306 of the Act made multiple amendments to the FSS program, including changes to the methodology for determining the size of the FSS program, expanding the definition of eligible families to include tenants of certain privately owned multifamily properties subsidized with Project-Based Rental Assistance (PBRA), updating the FSS Contract of Participation (CoP), reducing burdens on Public Housing Agencies (PHAs) and multifamily assisted housing owners, clarifying escrow account requirements, and updating the FSS Action Plan requirements. After consideration of public comments, this final rule incorporates these changes, responds to public comments, and further revises HUD's FSS regulations to further streamline the program for PHAs, multifamily property owners, and eligible families, including providing that families participating in the Housing Choice Voucher Homeownership Program and all Section 8 programs can participate in the FSS program, revising certain definitions that apply to the program to align with commenters' suggestions, making changes to the CoP provisions, revising the lists of activities for which forfeited escrow funds may be used, and making changes to portability provisions.