Single-Family Homebuyer Protection Act established; civil penalty. Establishes the Single-Family Homebuyer Protection Act for the purpose of prohibiting a covered entity from acquiring an interest in more than five single-family homes within the same county, city, or town in the Commonwealth on or after July 1, 2026. The bill provides that no seller of a single-family home shall enter into an agreement with a covered entity for acquisition of such home before publicly marketing such home to natural persons residing in the Commonwealth and first-time homebuyers for at least 10 calendar days. The bill allows the Department of Housing and Community Development to publish aggregated information using existing data, including (i) the number and percentage of single-family homes owned by covered entities, broken down by locality, zip code, and census tract, and (ii) identified trends in the concentration of covered entity interests in single-family homes. The bill allows the Attorney General to seek an injunction and a civil penalty to restrain any violation of its provisions.