The market for short-term rentals often involves platforms or agencies that collect payments on behalf of property owners. When those intermediaries deduct their fees and platform costs before passing funds to the host, questions arise about the correct tax base and the figures
that should appear in the annual Certificazione Unica. This article clarifies the rules governing the 21% withholding, explains which figure counts as the gross fee, and summarizes the latest guidance released by the tax authority on April 16, 2026.
Two core obligations intersect here: the duty of the intermediary as a sostituto d’imposta to calculate and pay the withholding, and the need to report contract data to the Agenzia delle Entrate. Clear
differentiation between the amount the guest pays and the net amount received by the owner is essential to avoid automated mismatches in the tax administration’s cross-checks. Throughout the text we use practical examples and suggest documentation practices to reduce the risk of queries or audits.
What intermediaries must declare and the general calculation rule
By law the intermediary who receives the payment on behalf of the host must apply the
21% withholding as an advance payment on rental income. The key principle is that the withholding base is the gross amount actually paid by the guest, not the net proceeds after commissions. Therefore, the intermediary should record the total contract value as the gross fee in the Certificazione Unica and show the corresponding 21% withholding calculated on that gross figure, even if the owner ultimately receives a smaller payment once platform or agency commissions are deducted.
Practical calculation example
Consider a concrete illustration: a guest pays €100 for a stay; the platform retains €10 and the intermediary keeps €15 in commissions. The host receives €75, but the withholding must be computed on the full €100, resulting in a €21 retention. That means the figures shown in the Certificazione Unica must list the €100 gross income and the €21 withheld, while reconciliation documents separately show the commission breakdowns that produce the net payout. Presenting the gross and the withheld amount transparently prevents discrepancies during automated cross-checks by the tax authority.
Recent changes and broader obligations for hosts and platforms
The tax agency updated its guidance on short-term rentals on April 16, 2026, reflecting legislative tweaks introduced by law 199/2026. One major change limits the number of units a private owner may operate under the short-term regime to a maximum of two apartments beginning with the 2026 tax period. Exceeding that threshold presumes an entrepreneurial activity, with different tax and compliance consequences. The guidance also reiterates that intermediaries and online platforms must transmit contract data to the Agenzia delle Entrate, including the owner’s identity, property address, contract duration and the gross amount, typically by June 30 of the year following the rental.
Tax options and payment timings
Hosts may opt for the cedolare secca regime on income from short-term rentals: standard rate rules remain in force, including a general 26% rate and a reduced 21% rate available under specific conditions to a single chosen unit. The withholding applied by intermediaries acts as an advance payment of the tax due. Intermediaries must also remit withholdings via F24 by the 16th day of the month following the payment. There are targeted exclusions: for example, payments made by check payable directly to the host or transactions where the intermediary only provides payment processing (card circuits) may fall outside the withholding obligation.
Avoiding mismatches: documentation and best practices
To reduce the likelihood of automated flags or requests for clarification, both intermediaries and hosts should adopt clear accounting practices. Contracts and platform statements should include explicit clauses describing how platform fees and intermediary commissions are calculated and retained. Intermediaries are advised to supply hosts with periodic reconciliations that show the gross amount, each withheld sum and the net transfer. Keeping copies of platform payout reports, credit notes and invoices allows the parties to prove how the certified gross income relates to the net credited amount when the Agenzia delle Entrate performs data matching.
Consequences of reporting discrepancies and practical tips
When the figures reported in the Certificazione Unica diverge from platform records, the tax authority’s automated systems often flag the case for further checks. That can trigger requests for documentation or extended inspections for both host and intermediary. Practical safeguards include retaining digital transaction extracts, agreeing in writing on reporting formats, and, when in doubt, seeking guidance from a tax adviser. Clear, consistent reporting that distinguishes gross fee, retained commissions and the 21% withholding is the most effective way to prevent misunderstandings and ensure compliance.