Progressive tax means that the marginal rate increases with income, so, no, BI plus flat tax isn&#x27;t (even viewing BI as negative tax) a smooth progressive curve, its still just a flat marginal rate.<p>If BI is also excluded from taxable income in an otherwise &quot;flat&quot; scheme, it&#x27;s effectively a two-tier progressive tax system (many proposed &quot;flat&quot; taxes without BI also follow this model), with a zero % bracket and one other bracket; still not a smooth progressive curve. A smooth progressive curve is when marginal (not total) tax rate is a continuous, monotonically increasing function of income (probably asymptotically approaching done limit.)