The Housing Market Transparency Act requires the Secretary of Housing and Urban Development to collect detailed information about properties that receive federal tax credits to finance affordable housing, then publish this data annually for public access. The bill affects state housing agencies and property owners participating in the low-income housing tax credit program, a major federal tool for creating affordable rental housing. States must submit comprehensive data on these properties—including development costs, ownership details, inspection results, and what happens when properties are sold or foreclosed—within 18 months of construction completion and every year after. HUD will establish standards for consistent data collection, provide technical assistance to states, and issue regular public reports on the affordable housing market, though the legislation does not specify new appropriations or major funding increases.