This bill, the "Unfunded Mandates Accountability and Transparency Act of 2025," significantly amends the Unfunded Mandates Reform Act of 1995 to enhance transparency and accountability in federal rulemaking. It defines a "major rule" as one likely to have an annual economic effect of $100 million or more, cause major cost increases, or result in significant adverse effects on competition or employment. For all such major rules, agencies must now prepare and publish detailed regulatory impact analyses (RIAs) , quantifying anticipated benefits and costs and exploring various regulatory alternatives. These RIAs must assess costs to State, local, and Tribal governments, estimate disproportionate budgetary effects, and analyze impacts on job creation or loss. The bill expands stakeholder consultation to include impacted private sector parties , including small businesses, throughout the rulemaking process. A key provision requires agencies to select the regulatory alternative that maximizes net benefits , with exceptions permitted only with OIRA approval and thorough justification. The Office of Information and Regulatory Affairs (OIRA) gains new responsibilities for guidance and oversight, ensuring major rules comply with the Act and do not conflict with other agency policies, and must report annually to Congress. Agencies must also establish an electronic docket and publish a notice of initiation for potential major rules at least 90 days before a proposed rule. Finally, the bill extends judicial review , allowing aggrieved persons to challenge agency compliance with RIA and net benefit requirements for major rules.