In Belgium

An unrealised gain (plus-value latente) is the difference between a property’s current market value and its acquisition price, when the property has not been sold. In Belgian tax law, unrealised gains are not taxable — tax on property gains only materialises upon sale, and only if the holding period is under 5 years (for built property).

This principle means a property can appreciate significantly over decades without generating any tax liability, as long as the owner does not sell.

How it works

No tax event. Unlike some countries, Belgium does not tax unrealised appreciation. There is no wealth tax, no annual revaluation tax, and no mark-to-market obligation for property held by individuals.

Refinancing. While not taxable, unrealised gains can be leveraged by refinancing: the owner takes out a new mortgage based on the property’s increased value, accessing cash without selling.

Inheritance. At death, the property is valued at its current market value for inheritance tax purposes. The unrealised gain is effectively crystallised, but it is the heir who bears the inheritance tax — not a capital gains tax.

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Good to know
In Belgium, there is no “step-up in basis” at death for capital gains purposes. However, since capital gains on property held over 5 years are already exempt, this is rarely a practical concern.

Practical example

Martine bought a house in Uccle in 2005 for 350,000 EUR. In 2026, comparable properties sell for 650,000 EUR. Her unrealised gain is approximately 300,000 EUR. She pays no tax on this gain. If she sells, the gain is tax-exempt (held over 5 years). If she passes it to her children, they pay inheritance tax on the 650,000 EUR market value.

Key considerations

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Warning
An unrealised gain is not guaranteed. Property values can decline, turning a paper profit into an unrealised loss. Market value assessments are estimates — the actual realised gain or loss is only determined at the point of sale.