Income tax law and policy are fundamentally intertwined with private markets—causal effects run in both directions. The vitality of public markets can be stifled or invigorated by the way that they are taxed. The power to tax is the power to destroy. In turn, the computation and collection of income taxes depends upon the valuation and liquidity provided by markets. Moreover, the economic properties of tax rules are contingent upon the underlying market structures. Changes to these structures induced by technological innovation can alter the efficiency and equity properties of the prevailing income tax rules. In this Article, I explain how innovations associated with the digital transformation of business will—as an unintended consequence—reduce the administrative barriers to taxing income and improve the economic tradeoffs, thereby making it both feasible and desirable to push outward the frontier of the income tax’s domain.