The Housing Acquisitions Review and Transparency Act would require large companies and investors to report to federal antitrust authorities when they acquire residential properties in a way that could reduce competition in housing markets. The bill modifies federal merger notification rules to treat all residential property purchases by a single buyer within a calendar year as one combined acquisition, meaning companies would have to file reports once their total purchases reach certain thresholds. This requirement would apply to acquisitions of single-family homes, multifamily buildings, condominiums, and manufactured homes intended for rental or investment purposes, but would exclude short-term rentals like hotels and vacation properties. The Federal Trade Commission and Department of Justice Antitrust Division would need to establish new rules defining what information and documentation companies must provide when filing these notifications. The legislation aims to give federal regulators better visibility into large-scale residential property purchases that could harm housing affordability and competition in local markets.