When it can occur and the cases admitted
The supplementary 730 can only be used if the error made in the ordinary form has resulted in economic damage. The rule identifies three very specific cases in which the use of the supplement is permitted:
- higher tax credit: when no deductible expenses have been indicated and you are therefore entitled to a higher refund;
- lower debt: when the omission of a data or the incorrect indication of an income led to paying more taxes than necessary in June;
- modification of the withholding agent: if the ordinary form was sent indicating an incorrect or no longer active employer to carry out the adjustment operations.
The fundamental rule established by the financial administration prohibits the use of the supplementary 730 if the error has caused a debt. Anyone who must pay additional sums is obliged to present the Personal Income Form by paying independently via F24.
Focus Home Bonus, the first year no data in the pre-compiled form
The building renovation and energy efficiency sector is the one that records the highest number of autumn corrections.
The main reason for this forgetfulness is the fact that, when you start to deduct a construction expense for the first time, the Tax Office does not automatically insert the figures into the expense framework. The data of the speaking transfers sent by the banks are simply listed in the information sheets attached to the declaration.
The reason is linked to the fact that it is possible to divide the deduction between several subjects who have incurred the expense (co-owners or family members), deciding how to settle until the last moment. In fact, it is sufficient to note on the invoice the amount incurred regardless of the share of ownership of the property. Since it is a free choice, the Revenue Agency does not insert anything in the pre-compiled form for the first year.
Also pay attention to the Furniture Bonus: in this case, in fact, there is no obligation to pay by bank transfer, for which the Revenue does not have the data available and does not fill out the declaration.
In subsequent years, however, the tax registry machine recognizes the continuity of the bonus and inserts the remaining installments automatically.
Other expenses not indicated
Other expenses that often “jump” from the 730 are those that entitle you to rent bonuses. For the rent of the main residence, a bonus linked to the contract is available for those with incomes of up to 31,000 euros, but obviously the data must be indicated manually.
The same goes for the deduction for off-site rentals.
When refunds arrive
The 730 Supplement allows you to enter the necessary data skipped in the first instance and therefore not lose the right to the deduction. From a procedural point of view, the modification cannot be carried out independently by the taxpayer via the pre-compiled web portal. It is mandatory to contact a CAF or a qualified professional (accountant or employment consultant), even if the previous declaration was sent by yourself. The intermediary has the duty to verify all technical documentation and invoices before transmitting the correct model.
As for reimbursements, the wait is always two months, so for the supplementary models the balance will arrive on the December paycheck (in January on pensions). In the case of taxpayers without a withholding agent, the refund will be paid directly by the Revenue Agency to the bank account, but the times in this scenario are extended until the following spring.
However, if the credit exceeds 4,000 euros, the Revenue Agency has the obligation to verify the conformity of the documents, checking the relevant bank transfers, the invoices of the companies and the certifications of the technicians. In this scenario, the refund will be released and paid directly by the financial administration to the current account, postponing the collection times up to six months from the October deadline.
|
Type of Error Detected |
Tool to Use |
Submission deadline |
Transmission Channel |
Refund Timing |
|---|---|---|---|---|
|
Forgotten expenses (More credit or less debt) |
730 Supplementary (Code 1) |
October 26, 2026 |
Only through CAF or authorized professional |
December pay slip or January pension. |
|
Incorrect or missing tax withholding agent (Data unchanged) |
730 Supplementary (Code 2 or 3) |
October 26, 2026 |
Only through CAF or authorized professional |
Follows the ordinary flows of the new substitute. |
|
Omitted or forgotten income (New debt for the taxpayer) |
PF Income Model |
November 30, 2026 |
Independently online or through an intermediary |
No refunds. Payment via F24 with redemption. |
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