The "Strengthening Oversight in Public Buildings Act" seeks to improve transparency and accountability in the management of federal public buildings. It amends the Thomas R. Carper Water Resources Development Act of 2024 to mandate that the Director and Administrator provide the Comptroller General of the United States with all data and reports concerning public building utilization, thereby strengthening external oversight. The legislation also clarifies and enhances oversight for federal agencies with independent leasing authorities , requiring the Director to identify these agencies and ensure their compliance with reporting requirements. Furthermore, it allows the General Services Administrator to retain a federal building as "swing space" to facilitate the sale or major renovation of other federal properties, provided the cost does not exceed realized savings and annual plans are submitted to Congress. To further support federal asset management, the bill extends the operational period of the Public Buildings Reform Board from December 31, 2026, to December 31, 2028. It also requires the Director of the Office of Management and Budget and the Administrator to provide the Board with all relevant public building utilization data and reports.