A tax penalty that had been part of Belgian law for decades has just been removed — for one category of taxpayer only. The Act of 15 July 2026 reforming personal income tax, published in the Belgian Official Gazette of 29 July 2026, ends the surcharge for insufficient advance tax payments for people who trade in their own name. Companies stay exactly where they were.
From assessment year 2027 — that is, on 2026 income — the surcharge for absent or insufficient advance payments is abolished for business profits, professional income and assisting-spouse remuneration. The bonus survives, and a fifth payment window is created (21 December – 20 February). Under corporate income tax nothing changes: the surcharge remains due, at 6.75% for assessment year 2027.
The measure attracted little comment in a statute dominated by the tax-free allowance, the phasing out of the marital quotient and the new 20% cap on lump-sum benefits in kind. It deserves attention from anyone weighing sole-trader status against operating through a company, because it widens the gap between the two.
What the statute actually removes
The mechanism concerned sits in Articles 157 and following of the Belgian Income Tax Code. A taxpayer receiving income not subject to withholding at source must spread the tax over four quarterly payments; failing that, the final assessment is increased by a surcharge. That surcharge is what disappears.
One reading point matters, because the statutory wording has already produced inaccurate summaries. The abolition covers three income categories: business profits, professional income and remuneration paid to assisting spouses. The qualifier "assisting spouses" attaches only to the third category. Every trader, operator and farmer earning business profits, and every member of a liberal profession earning professional income, is therefore covered — not just assisting spouses.
The effective date is 1 January 2026: payments relating to assessment year 2027 and later years are no longer backed by a penalty.
The bonus survives — and a fifth window opens
Removing the stick does not remove the carrot. The bonus regime remains in place: a self-employed taxpayer who pays voluntarily still receives a tax credit, larger the earlier the payment falls. The classic calendar is unchanged — 10 April, 10 July, 10 October and 20 December.
The statute adds a fifth window, running from 21 December of the income year to 20 February of the following year, carrying a bonus equal to 0.5 times the reference rate, against 0.75 times for the fourth window. The first such window runs from 21 December 2026 to 20 February 2027: a payment made in early February 2027 will still affect tax on 2026 income.
An advance payment stops being a penalised obligation and becomes an optional use of cash that carries a return. For a sole trader with lumpy cash flow, the fifth window is real flexibility: the decision can be taken once the year's result is known, rather than on an April estimate.
Company directors are treated differently
This is the point most summaries drop. The abolition targets business profits and professional income — the earnings of someone trading in their own name. It does not target director's remuneration, where the obligation to pay in advance survives, in combination with payroll withholding tax: an advance payment is due only to the extent that tax has not already been withheld at source.
The statute also redraws the payment windows for that category from assessment year 2028 (amended Article 159 of the Income Tax Code): payments must be made from 21 February onwards, and no later than 10 April, 10 July, 10 October and 20 December of the income year.
Payments made between 21 December of year X and 20 February of year X+1 will be allocated to taxable period X. They will no longer count towards year X+1. A director who managed year-end cash by paying in January will find the mechanics shifted by a full year — build this into cash planning from the winter of 2027-2028.
Under corporate income tax the surcharge stands in full
For a company whose financial year matches the calendar year, the reform changes nothing about advance payments. Three points:
- The surcharge rate for assessment year 2027 (2026 income) is 6.75%, against 9% for the previous assessment year.
- The surcharge bites from the first euro of tax due and is not tax deductible: it is a genuine increase in tax, not a cost.
- Article 218, § 2 of the Income Tax Code continues to exempt a small company's first three financial years — the corporate counterpart of the historic tolerance granted to newly established sole traders.
A structural difference is often misread. Under corporate income tax, advance payments generate no bonus in the personal-income-tax sense. They produce a credit that neutralises the surcharge, without ever creating a net gain. Paying more than necessary earns nothing; the excess is simply refunded, without interest.
A transitional rule applies to the first window of assessment year 2028, which runs from 21 December 2026 to 10 April 2027.
The entrepreneur's deduction: worth keeping in proportion
The same statute inserts a new Article 81 into the Income Tax Code: the "entrepreneur's deduction", reserved for self-employed individuals whether in a main or a secondary occupation. The mechanism exempts 10% of "adjusted" business profits and professional income, the adjustment excluding items such as compensation for a temporary loss of income, attendance fees and separately taxed income.
The cap defines the real scope: EUR 311 unindexed, which after indexation lands in the region of EUR 650, rising to EUR 415 unindexed from assessment year 2030. The deduction applies from assessment year 2028 and is expressly excluded under corporate income tax (Article 198quater of the Income Tax Code).
For a sole trader with EUR 60,000 of net professional income, the theoretical 10% deduction would be EUR 6,000; the cap reduces it to a few hundred euros. Actual tax saved runs into tens of euros at the marginal rate. This is a political signal to individuals, not an optimisation lever.
What this shifts in the sole-trader versus company decision
Every reform of this kind moves the break-even point between trading in one's own name and trading through a company. Here two effects push the same way and a third pushes back.
On the individual side: a cash-flow penalty removed and a deduction added, modest but real. On the company side: the surcharge retained in full, plus — in the same statute — a higher minimum director's remuneration required for the reduced corporate rate and the 20% test on lump-sum benefits in kind. The third effect runs the other way: none of these constraints touches the structural mechanisms for which a company remains the only vehicle — liquidation reserve, VVPRbis, tangible assets on the balance sheet.
The practical conclusion is unglamorous and rarely drawn: the sole-trader-or-company question is not settled on a single measure. It is settled on the sum of the flows — remuneration, dividend, reserve, assets held — over a horizon of several years. Our tax simulator is designed to put numbers on that before anyone gets into the detail.
The figures and dates above are drawn from the Act of 15 July 2026, published in the Belgian Official Gazette of 29 July 2026, and from the parliamentary record. They do not replace analysis of your own position by your accountant or tax adviser.
Frequently asked questions
Which Belgian self-employed taxpayers no longer face a surcharge for insufficient advance payments?
The Act of 15 July 2026 reforming personal income tax, published in the Belgian Official Gazette of 29 July 2026, abolishes the surcharge for absent or insufficient advance tax payments for taxpayers earning business profits, professional income or remuneration as an assisting spouse. It therefore covers all traders, operators and farmers earning business profits, and all liberal professions earning professional income, when they operate in their own name — not only assisting spouses. The measure takes effect from assessment year 2027, meaning it already applies to 2026 income.
Is it still worth making advance tax payments in Belgium once the penalty disappears?
The bonus regime is retained, so a self-employed taxpayer who pays voluntarily still obtains a tax credit, and the credit is larger the earlier the payment falls. Advance payments therefore shift from being a penalised obligation to being an optional tax-efficient use of cash. The reform also adds a fifth payment window running from 21 December of the income year to 20 February of the following year, carrying a bonus equal to 0.5 times the reference rate against 0.75 times for the fourth window.
Does the 2026 reform change advance tax payments for a Belgian company?
No. Under corporate income tax the surcharge rules are unchanged, and the rate for assessment year 2027 — covering 2026 income — is 6.75%, against 9% for the previous assessment year. The surcharge applies from the first euro of tax due and is not tax deductible, since it is a genuine increase in tax rather than a deductible cost. Article 218, § 2 of the Belgian Income Tax Code continues to exempt the first three financial years of a small company. A company director also remains required to make advance payments on director's remuneration to the extent that tax is not already withheld at source through payroll withholding tax.