Abstract
<title>Abstract</title> <p> Between January 2024 and December 2025, Türkiye’s tax administration pulled more than 900,000 unregistered landlords into the income-tax net through data matching, field inspections, and a mandatory bank-transfer rule a 41.5% expansion of the rental-income taxpayer registry in two years. Rents surged simultaneously, feeding a live public claim that formalization costs were passed through to tenants. This paper provides the first evidence on the rent incidence of landlord income-tax enforcement in any market. We combine the Central Bank’s new hedonic new-tenant rent index (YKKE; 19 regional strata, monthly, 2018–2026) with a predetermined measure of regional enforcement exposure campaign-revealed landlords per tenant household built from the province-level taxpayer registry. Because a national 25% rent cap expired in July 2024, we separate the enforcement shock from the cap release using a cap-bite control computed from never-capped new-contract rents. Estimates that ignore the cap release suggest sizeable pass-through (+ 5.7 log points per standard deviation of exposure); conditioning on cap-bite eliminates pre-trends and collapses the estimate to + 1.1 log points (wild-cluster bootstrap p = 0.48; randomization-inference p = 0.34), with no differential response of house prices. The confidence interval cannot reject full pass-through of plausible effective tax burdens a power constraint we quantify but it bounds the campaign’s contribution to the 2024–2026 new-tenant rent surge at one-fifth under generous extrapolation, with a point estimate near six percent. What looks like tax pass-through in the raw data is, almost entirely, the fingerprint of rent-cap release. <bold>JEL codes:</bold> H22, H26, R31, R38 </p>