One line in the offer, and a tax bill for a right you cannot use

"The options may not be exercised before 1 January 2030, may not be transferred, and the exercise price is fixed at the date of this offer. Please sign and return within sixty days." That is the operative part of most Belgian option offers, and it does more work than the vesting schedule above. Stock options in Belgium are taxed at grant, not at exercise and not on sale. The person who signs owes income tax that year on a right they cannot touch until 2030, in a company with no share price.

Three questions follow every offer: what have I been given, why is the tax number what it is, and what happens if I move country. The last one comes up more often now, because the plan is drafted in Dublin and applied to three people in Antwerp.

What are stock options under Belgian law, and what gets taxed

The regime sits in articles 41 to 47 of the law of 26 March 1999 on the Belgian action plan for employment. An option is the right to buy, or to subscribe on a capital increase, a determined number of shares at a determined price during a determined period. Performance, good and bad leaver, acceleration on a change of control: none of it is in the law. It lives in the plan and the shareholders' agreement.

Tax attaches at grant. The option is deemed granted on the sixtieth day following the offer, provided the beneficiary accepts in writing inside that window, and it is taxable then even where exercise depends on conditions that may never be met. What is taxed is not the gain. For an unlisted option it is a flat 18% of the value of the underlying share at the offer, plus 1% for each year beyond the option's fifth, taxed at the beneficiary's marginal rate plus municipal surcharge. The share value is set on the binding opinion of the statutory auditor and cannot fall below the book value in the last approved annual accounts.

One exclusion matters for international plans: a promise of free shares is not an option, so restricted stock units sit outside the 1999 regime and are taxed on delivery at market value, as ordinary remuneration with contributions due.

Why the number is 9%, and what the plan gives up to get there

The 18% is halved to 9%, and the annual uplift to 0.5%, if the plan accepts a set of restrictions. They apply together, and losing one loses the whole reduction:

• The exercise price is fixed definitively at the offer.
• The option cannot be exercised before the end of the third calendar year following the year of the offer, nor after the tenth year.
• The option cannot be transferred between living persons.
• The grantor gives no protection against a fall in the value of the shares.
• The option relates to shares of the employing company or an affiliated company.

That second condition is counted in calendar years, and badly timed plans lose a year of everybody's life to it. An offer made in January 2026 becomes exercisable on 1 January 2030, four years of waiting. The same offer made in November 2026 opens on that same date, after three years and two months. The month you launch the plan matters as much as its contents.

Where the offer and the acceptance comply with the law, the benefit also escapes social security contributions. Set the exercise price below the share value at the offer, though, and the discount becomes ordinary remuneration with contributions due on it.

What happens if the shares end up worth nothing

The tax paid at grant is definitive and non-recoverable, due whether the options are exercised or not. Someone who paid a few thousand euros in 2026 on 9% of a share value that never materialised funded a loss out of net salary, and no later return corrects it.

There is a way to handle it, and it has to be built in advance. An employer can compensate the loss on underwater options without creating a new taxable benefit and without the reduced 9% valuation being clawed back, as long as the compensation stays within the rules of the plan and the beneficiary keeps a real exposure to a fall in the share value. So it has to be written in while the plan is a draft.

The quieter cost is behavioural. Someone who has paid tax on a right they cannot exercise starts behaving like a creditor rather than an employee. In a management package inside a transaction that is deliberate and priced. In an unexplained option plan it surfaces as a liquidity request during due diligence.

What changes the answer: who grants the option, and where the person lives

Belgium taxes at grant. Most other countries tax at exercise, so for anyone who moves during the life of an option the two systems never meet, and the result can be economic double taxation on the same value. An engineer arriving from London with live options has paid nothing yet and expects the bill at exercise. A Belgian resident who accepts an offer here and moves to Germany in year two has paid in full on something they may never use.

The second cross-border point catches foreign parents out. Since 2019, where a Belgian employee receives options or share-based benefits from an affiliated foreign company, the Belgian employer is deemed to have granted them: it reports the benefit on fiche 281.10 and withholds Belgian professional withholding tax, having done nothing but employ the person. Not reporting exposes the employer to a penalty. So the payroll has to find tax on a benefit that pays no cash, and group headquarters rarely warns the Belgian entity in time.

Since 2026, the exit is priced differently

The Belgian capital gains tax on financial assets, published in the Moniteur belge on 21 April 2026, applies to gains realised from 1 January 2026, at 10% above an annual exemption of EUR 10,000 per taxpayer. Holders of at least 20% of a company fall under a separate regime, progressive and with the first EUR 1 million exempt, that almost no option beneficiary reaches.

For an option holder the rule that decides everything is the acquisition value. Shares obtained on exercise of a qualifying option are not treated as acquired at the exercise price paid, but at their market value at the moment of exercise. The appreciation up to exercise stays outside the tax, and a sale immediately after exercise leaves a base close to zero. An option transferred rather than exercised takes what it was worth when it became exercisable.

With the three calendar year block on top, the exercise date becomes a decision. Exercise three years before a closing and you pay 10% on three years of appreciation. Exercise shortly before it and there is almost nothing to declare. Anyone who moves has two more rules to check: arrival in Belgium resets the acquisition value to the market value on arrival, and departure counts as a disposal, with payment deferred on a move inside the EEA or to a country with a tax treaty.

What Belgian founders use instead

Warrants sit under the same 1999 law, built the other way round: immediately exercisable and transferable, so the halving conditions are out of reach and the flat 18% applies. They work as an alternative to a cash bonus, because the benefit escapes social security contributions where the conditions are met. A warrant pays someone, it does not keep them.

Phantom shares, or stock appreciation rights, give no share at all: the beneficiary receives cash calculated on the increase in the value of the company between grant and exercise. The payout is income under article 31 of the Income Tax Code 1992 and carries social security contributions, but it is taxed on payment and only where there is something to pay: no risk for the beneficiary, no dilution for existing shareholders, a charge on cash at exit.

The profit premium is withheld at a rate well below ordinary pay, after a 13.07% solidarity contribution and with no employer contributions, and it is capped as a share of the gross wage bill. It goes to every employee, differentiated only by objective category, so it is useless for three key hires and good for a whole team in a strong year.

The dups approach

What an option plan needs before it is drafted is a dated calendar and a share value somebody can defend. We work backwards from the probable exit: the latest month the offer can go out for the exercise window to open before a closing, the value to put on the underlying share and the auditor opinion that supports it, and the euro amount each beneficiary pays out of their own pocket in the year they accept. That last figure is the one nobody calculates before the offers are printed, and it decides whether the plan motivates or irritates.

This is Specialist Support work: sizing the pool in the cap table before the round, choosing between options, warrants, phantom shares and a profit premium, valuing the underlying share, drafting the plan and the acceptance letters, then testing the result against the vesting and leaver clauses you agreed with your investors. For a group hiring into Belgium from abroad the question is narrower and easier to get wrong: which entity carries the fiche 281.10 reporting and the withholding on a benefit it never granted.

Whichever instrument you choose, your beneficiaries become minority shareholders the day they exercise, holding rights that are far easier to define now than to concede then. Our list of governance rights worth negotiating sets those questions out in the order they arrive, and an hour is usually enough to tell you whether your calendar still holds.

Frequently asked questions

Do I pay tax on my stock options in Belgium even if I never exercise them?

Yes. The benefit is taxed at grant, deemed to happen on the sixtieth day after the offer if you accept in writing within that period. The tax is definitive and cannot be recovered if the option ends up worthless. Some employers compensate that loss, but the mechanism has to be written into the plan before you accept.

How long do I have to wait before I can exercise options in Belgium?

For the reduced 9% valuation, the plan has to prevent exercise before the end of the third calendar year following the year of the offer, and after the tenth year. An offer made in 2026 opens the window on 1 January 2030. Without that blocking clause the valuation stays at 18% and the wait disappears.

My employer's foreign parent offered me options. Does the Belgian regime apply?

It can, because the law allows options on shares of an affiliated company, but only where the plan meets the Belgian conditions and you accept in writing within sixty days. The paperwork is not optional: your Belgian employer reports the benefit on your fiche 281.10 and withholds Belgian tax on it, even though the grant came from abroad.

Elena Vromans, Legal Counsel at dups