What is an ESOP?
An Employee Stock Option Plan gives employees the right to buy shares in their company, usually at a fixed price set at the time of the grant. The idea is simple: if the company grows and exits, those shares are worth more than what you paid for them.
For companies, it solves a real problem. You can’t always match the salary a larger firm offers. But you can offer a stake in what you’re building. For the right hire, that trade-off is genuinely compelling.
For employees, it’s a chance to share in the value you help create. That’s not a small thing.
How it works in practice
Options don’t convert to shares on day one. They vest over time, and usually come with conditions attached: a vesting period, a minimum employment term, sometimes performance targets too.
The standard structure is four years with a one-year cliff. Nothing vests in year one. After that, 25% unlocks at the end of year one, then linearly to 100% at year four. Monthly vesting after the cliff is common.
The logic is sound: equity should reward the people who stay and contribute.
The Belgian tax angle
Belgium has a specific regime for stock options, and it tilts in your favour if you understand it.
In most countries, you get taxed when you exercise your options. Belgium lets you choose to be taxed at grant instead, if you accept within 60 days. The taxable benefit is calculated as:
Number of options x exercise price x applicable percentage
The base rate is 18% for options with a lifetime up to five years, rising 1% per year beyond that. Under certain conditions, that percentage is halved: the exercise price matches fair market value at grant, the options are non-transferable, no guaranteed return, not employer-financed, and the employee carries the full economic risk.
That upfront tax is treated as professional income, taxed progressively between 25% and 50%. But here’s the important part: any future gain at exit isn’t taxed again as income. You pay once, early. If the company performs well, that’s a genuinely good deal.
What happens when you raise again
Every funding round creates new shares. Your percentage goes down. That’s dilution, and it comes with the territory.
It doesn’t mean your equity is worth less. If the round is at a higher valuation, the share price has moved up. A smaller slice of a much bigger company is usually the better outcome. The math tends to work in your favour when growth is real.
What to keep in mind
The Belgian system gives you a choice: pay tax at grant, or go the classical route and pay when you exercise. If you opt for upfront taxation and the company grows, any gain at exit is no longer taxed as income. That’s the trade-off worth understanding.
Leaving before your options fully vest usually means losing the unvested portion. Some plans also require you to exercise vested options within a set window after departure.
None of this makes ESOPs a bad deal. It makes them a deal worth understanding before you sign.
The bottom line
ESOPs are one of the more tangible ways a company can say: we want you to win when we win. Understanding the mechanics, the tax options, and what dilution actually means in practice is how you turn that offer into something real.
About the model
This table puts numbers to the concepts above. It assumes annual funding rounds, which means ongoing dilution alongside a growing valuation. Vesting follows the standard four-year schedule with a one-year cliff. The model assumes an exit in 2029 at €100 million.
These are working assumptions, not predictions. The model is designed to make the mechanics tangible. Your numbers will depend on your grant size, your company’s trajectory, and the terms of your plan.
This is for general information only. Tax and legal treatment depends on individual circumstances and company policy.
