Bulgaria
Taxed as self-employment income (not capital gains). The 10% flat rate plus a 25% deemed-expense allowance gives ~7.5% effective income tax, but capped social contributions add a meaningful extra burden.
Self-employment / freelance (business) income - registered as a freelancer (svobodna profesiya) or sole trader; not capital gains.
10% flat PIT; freelancers get an automatic 25% deemed-expense deduction, giving a ~7.5% effective income-tax rate.
Mandatory social + health contributions ~27-32% of a declared insurable base, capped (2026 max base ~EUR 2,112/month).
Register as freelancer/self-insured person or sole trader; quarterly advance tax, annual return by 30 April.
USDC valued in BGN/EUR at receipt = taxable business income; later disposal of the crypto is a separate event.
Prop firms based in Bulgaria
Their payout history is tracked on-chain by Tradavi.