Yemen
Taxed as ordinary business income at ~10-15% (up to ~20%) with no social charge on the self-employed, but enforcement is weak. The real obstacles are the civil war, a split banking system, a collapsing rial, and sanctions, so receiving and converting USDC is largely informal, risky P2P.
Self-employment / business income (commercial, industrial and non-commercial activity under Income Tax Law 17/2010); residents taxed on worldwide income; NOT capital gains.
Progressive ~10-15% (some bands up to ~20% on the highest incomes).
Self-employed excluded from the mandatory social-insurance scheme; effectively no contribution.
Self-employed nominally register and file, but administration is fragmented due to civil war and the north/south split.
Legal grey zone; no crypto tax law; USDT/USDC widely used via P2P as a rial hedge but access is constrained by conflict and sanctions on Houthi-linked finance.