Just some stuff about me.
Box 1 - work & home: salary, wages, business income (self-employed), benefits, income related to primary residence
Box 2 - substantial interest: own ≥5% shares in private company (BV)
Box 3 - savings & investments: savings accounts, investments (stocks, ETFs), second homes, crypto, minus debts
Employer automatically withholds income tax:
If your net worth is above the tax-free bracket of box 3, it may be worth it to start a BV that does investments, e.g. via Ligo.
3 pillars: