Income taxes (Tables)

12 Months Ended

Dec. 31, 2025

Income Taxes [Abstract]

Summary of Income Tax Expense

	2025			2024			2023
	€			€			€
Current income tax expense		(1,087,278	)		(1,033,115	)		(473,623	)
Deferred tax (charge)		(900,623	)		(791,909	)		(575,182	)
Income tax (expense)		(1,987,901	)		(1,825,024	)		(1,048,805	)

Summary of Reconciliation of Income Tax Benefit / (Expense) And The Accounting Loss

Reconciliation of income tax benefit / (expense) at statutory tax rate and the income tax benefit / (expense) as reported in the consolidated statement of profit or loss and other comprehensive income is as follows:

	2025			2024			2023
	€			€			€
Loss before income tax		(173,711,496	)		(132,396,503	)		(99,826,263	)
Income tax at statutory income tax rate in the Netherlands (2025, 2024 and 2023: 25.8%)		44,817,566			34,158,298			25,755,176
Effect of tax rates in other countries		(24,993,816	)		(17,611,881	)		(14,334,369	)
Recognition (derecognition) of previously unrecognized (recognized) deferred tax assets		270,882			762,594			(58,506	)
Current period losses for which no deferred tax asset has been recognized		(22,244,353	)		(17,950,456	)		(14,771,877	)
Nondeductible expenses		(891,058	)		(1,085,015	)		(458,482	)
Prior period adjustments		1,052,878			(98,564	)		2,819,253
Income tax (expense)		(1,987,901	)		(1,825,024	)		(1,048,805	)

Summary of Tax Loss Carry-forwards Incurred In Current And Prior Years

Tax loss carry-forwards incurred in current and prior years will expire as follows:

	Switzerland		Netherlands		Tax losses
Year	€		€		€
2027		103,161,581		—		103,161,581
2028		74,599,050		—		74,599,050
2029		108,339,820		—		108,339,820
2030		323,032,344		—		323,032,344
Unlimited		—		33,892,029		33,892,029
Total carry-forward losses		609,132,795		33,892,029		643,024,824

Summary of Movements in Deferred Tax Balances

	R&D		Fixed			Non-current provisions
	expenses		assets			and liabilities			Total
Deferred tax assets	€		€			€			€
At January 1, 2025		1,901,513		—			626,838			2,528,351
(Charged)/credited
- Profit or (loss)		46,119		—			483,602			529,721
- Currency translation differences		—		—			(90,558	)		(90,558	)
At December 31, 2025		1,947,632		—			1,019,882			2,967,514
Deferred tax liability
At January 1, 2025		—		(152,491	)		(1,901,513	)		(2,054,004	)
(Charged)/credited
- Profit or (loss)		—		2,388			(46,120	)		(43,732	)
- Currency translation differences		—		17,574			—			17,574
At December 31, 2025		—		(132,529	)		(1,947,633	)		(2,080,162	)
Net deferred tax assets at December 31, 2025										887,352
	R&D		Fixed			Non-current provisions
	expenses		assets			and liabilities			Total
Deferred tax assets	€		€			€			€
At January 1, 2024		1,754,773		—			400,200			2,154,973
(Charged)/credited
- Profit		146,740		—			193,381			340,121
- Currency translation differences		—		—			33,257			33,257
At December 31, 2024		1,901,513		—			626,838			2,528,351
Deferred tax liability
At January 1, 2024		—		(12,671	)		(1,754,773	)		(1,767,444	)
(Charged)/credited
- Loss		—		(133,628	)		(146,740	)		(280,368	)
- Currency translation differences		—		(6,192	)		—			(6,192	)
At December 31, 2024		—		(152,491	)		(1,901,513	)		(2,054,004	)
Net deferred tax assets at December 31, 2024										474,347