The point is not an increase in taxes due, which are calculated based on income and deductions due, but the shorter time available to distribute the payment. In fact, if the 730 results in a debit balance, the withholdings are concentrated in a shorter period, with a possible significant impact on the next salaries or pensions.
For further information: Model 730/2026, when does the penalty start for those who do not submit the declaration?
The adjustment can be closed in two ways: with a credit, which is returned to the taxpayer, or with an amount to be paid, which is recovered directly from the withholding agent. The negative balance can emerge when, at the end of the calculations, the taxes already paid during the year are lower than those actually due. It is an eventuality that may concern, for example, those who have had multiple employers during the same year without an overall adjustment, or those who receive rental income subject to flat tax.
For further information: Refund 730/2026, for some taxpayers there is a risk of postponement to March 2027
The difference for those who present the 730 in recent months mainly concerns the possibility of paying the amounts in instalments. The balance and the first deposit can in fact be divided into several tranches, but the number of usable installments is progressively reduced as the deadline for the declaration approaches. Those who send the form in September may therefore have just two or three installments available to recover the amount owed. The practical consequence is that each individual withholding tax can be significantly higher than that applied to those who submitted the declaration further in advance. The withdrawal is made directly by the employer or the institution that provides the pension, as a withholding agent.
To further complicate the picture there is the calendar of advance payments. In fact, the second or only tax advance must be paid in November, a sum which, unlike the balance and the first advance, cannot be divided into installments. The amount is then retained in full in the November month. In this way two components can be added: the close installments necessary to pay off the debt resulting from the 730 and, at the same time, the tax advance expected for November. For the taxpayer, the result can translate into a particularly significant reduction in the net amount of the salary or pension in that month.
In fact, the mechanism also applies to pensioners. The Revenue Agency provides that, when the declaration shows a debt amount, the withholding agent proceeds with the recovery through a withholding from the pension. In the case of those who have indicated INPS as withholding tax, the operations relating to the 730/2026 adjustments are still underway. After the millions of adjustments, both credit and debit, carried out by the institute in the month of August, the September installment also continues to be affected by the processing of the declarations sent at a later time.
However, there is a possibility to prevent the November withdrawal from being higher than necessary. The taxpayer can ask his withholding agent to reduce or eliminate the second advance payment, but only if he has sufficient elements to foresee that the tax actually due will be lower than that taken as a reference for the calculation of the advance payment. The request must be submitted by October 10th. An example could concern those who have terminated a rental contract with flat rate tax during the year and, consequently, expect a lower income for the year than that used to determine the deposit. Another hypothesis is that of a taxpayer who has incurred numerous deductible expenses, such as to reduce the overall tax due.
The possibility of reducing the second down payment, however, should not be used without a reliable forecast. You need to have reasonable assurance that your final tax will actually be less. A payment that is too low compared to what is actually due can in fact lead to penalties, which remain the responsibility of the taxpayer. In any case, it should be remembered that presenting the 730 in September therefore does not increase the amount of taxes due. The tax debt depends exclusively on the income situation and the deductions due to the taxpayer. What changes, however, is the way in which the sum is recovered: arriving late for the presentation means having fewer monthly payments available to distribute the withholdings. If you add to this the advance payment entirely due in November, the overall burden on your salary or pension can become particularly significant.
For further information: Tax return and 730, deductions for children's music courses: what to know
