Think of NIT as steepening the progressive tax rate curve, and allowing it to dip below the y (tax rate) axis for sufficiently low x (income). There exist sever

Think of NIT as steepening the progressive tax rate curve, and allowing it to dip below the y (tax rate) axis for sufficiently low x (income). There exist several “refundable tax credits” today in the US that effectively do this at a small scale, albeit with a lumpy phase-out curve that runs into the same disincentive cliffs as many other welfare programs. UBI, on the other hand, shifts the curve rightward, so everyone’s income is relatively higher and is thus subject to more taxes. (You’d obviously also need to raise taxes overall if your goal is to keep it budget-neutral).