When a homeowner lets a vacant flat be used by a close relative without charge, there are more implications than just family convenience. Owners who grant a property in comodato d’uso gratuito — commonly described in English as a family loan — may qualify for a specific IMU reduction if they follow the required
formalities. Understanding how the tax base is calculated, which documents to file and how municipalities can independently adjust rates helps convert a household decision into real fiscal savings.
This article explains the mechanics of the relief linked to the family loan, the administrative checks that typically arise, the new local options available from 1 January 2026, and the separate update on coefficients for properties without a cadastral income,
set by the MEF decree of 6 March 2026. It also summarizes recent clarifications from the Agenzia delle Entrate about the procedural steps when tax offices issue preliminary acts.
How the family loan affects the IMU calculation
Relief for a property granted free to a direct-line relative operates by shrinking the base imponibile rather than changing the municipal rate. The process begins with the property’s rendita catastale,
which is first revalued and converted to a taxable base using the standard cadastral multipliers. If conditions are met — notably that the house is usable as the beneficiary’s main residence and the agreement is a genuine comodato — the taxpayer can apply a 50% reduction to that calculated base. After this reduction is applied, the municipality’s aliquota IMU is multiplied against the lower base to produce the final tax due.
Eligibility, registration and paperwork
Who qualifies and who is excluded
To benefit, the loan must be a true gratuitous arrangement between parents and children (direct line). The contract must be registered with the Agenzia delle Entrate, and the beneficiary must establish the property as their principal residence. Agreements with friends, distant relatives, or arrangements that involve rent — including short-term rentals — do not qualify. In short, the relief is narrowly targeted: it is for the classic comodato familiare between parents and offspring, and not a vehicle for reducing IMU on second homes or investment properties.
Documents, controls and practical tips
Municipalities can check that the declared situation matches reality. Keep a register-ready set of paperwork: a copy of the registered comodato, tenant/resident self-certifications, and any proofs showing absence of rent. Proper documentation reduces the risk of challenges and eases administrative verification. If a council queries the arrangement, having clear, dated records and the registration receipt is often decisive.
Municipal options and the 2026 coefficient update
Starting 1 January 2026, municipalities may optionally cut the IMU rate by up to 50% for certain categories of second homes that are not rented and are used only occasionally, for example during holidays. This is a distinct instrument: while the family loan halves the taxable base, the municipal measure reduces the rate. Since adoption is discretionary, owners of multiple properties should review local council deliberations annually, submit any required applications and supply supporting documentation to claim the reduction when offered.
Separately, the MEF issued a decree on 6 March 2026 updating the coefficients used to determine the IMU base for buildings that lack an assigned cadastral income (such as constructions in progress or certain category D properties). The coefficient for 2026 is set at 1.01, down from 1.03 in 2026. This figure is used to adjust historic construction costs or accounting values into the base imponibile for taxation purposes and is especially relevant for companies owning industrial and special-purpose buildings.
Administrative procedures: contraddittorio and adhesion
The Agenzia delle Entrate has clarified procedural rules about the internal consultation known as the contraddittorio. When an office issues a draft assessment, taxpayers receive the schema of act and a minimum of 60 days to present observations and to access the file, under the modification introduced by art. 13, comma 1, lett. a), D.Lgs. n. 192/2026 and the general rule in art. 6‑bis, Law n. 212/2000 (as amended by D.Lgs. n. 219/2026). If the final act ignores points raised by the taxpayer, it must state the reasons for rejection. The MEF decree of 24 aprile 2026 lists narrow exceptions where the right to contraddittorio does not apply, for example in largely automated acts or those affecting urgent collection.
Where an accertamento con adesione is possible, taxpayers may file a request within 30 days of the schema, or within the subsequent 15 days following notification of an assessment that was preceded by a schema. Timelines may be extended in specific circumstances so that the administration’s power to notify acts is preserved; for instance, procedural rules can shift certain deadlines to ensure at least a 120‑day window in which the office completes its activity.
Final considerations
Granting a home to a parent or child without charge can yield a meaningful IMU saving if the eligibility conditions are respected and the paperwork is correct. At the same time, the optional municipal discounts introduced from 1 January 2026 and the updated coefficient fixed on 6 March 2026 for non‑cadastral buildings are separate levers that owners should monitor. Regularly review local council resolutions, retain registration receipts and self-certifications, and consult a tax professional when complex situations arise to convert family arrangements into legitimate fiscal advantages.