Why off-market home sales may be raising your property taxes

Off-market home sales in states with nondisclosure laws—such as Mississippi, Texas, and Wisconsin—are raising concerns about property tax fairness. When sale prices remain hidden, appraisal districts rely on incomplete data, including voluntary surveys and mortgage records, to estimate home values. Sergio Gárate, a real estate researcher at Emory University, found that newcomers like himself often lack access to local sale prices, creating an information gap that benefits long-term residents who can selectively disclose data. In Texas, Leana Mann, chief appraiser of the Travis Central Appraisal District, confirmed that appraisal districts must work with limited data. John Brusniak, a property tax attorney, noted that homeowners sometimes withhold sale details, forcing assessors to rely on guesswork. If estimates are too high, closing statements can correct the record—but if they’re too low, homeowners pay less in taxes. Gárate’s research links nondisclosure laws to higher appraisal bias and mortgage default risks for financially constrained borrowers. His 2025 study found that states with strict secrecy face greater disparities in property valuations. Meanwhile, New Mexico’s past experience as a nondisclosure state highlights the potential for tax revenue loss when sale data is hidden, though reforms in 2004 improved transparency. The debate over private listings has expanded beyond fairness to tax equity, as hidden sales may allow some homeowners to lower their bills while others face higher assessments. States like New York are now considering legislation to address the issue, with a proposal awaiting Governor Kathy Hochul’s approval. Critics argue that secrecy undermines the fairness of property tax systems, which rely on comparable sales data to determine assessments.