The messy boundary between pass-through and corporate taxation.

The article focuses on the boundary between individual income taxation and entity-level (corporate) taxation of businesses, examining its implications for firm behavior, economic measurement, and tax policy. It highlights the coexistence of these two tax approaches—individual-level "pass-through" taxation, where business income is taxed as personal income, and corporate taxation, where the firm is taxed as a separate entity—and discusses how organizational form choices respond to tax incentives and affect income measurement, particularly inequality and labor-capital income shares. The article also addresses challenges in aligning taxable income with economic income due to differences in timing and realization of corporate profits versus individual income, and considers the administrative and structural reasons why both tax forms persist. Finally, it suggests that defining the boundary between these tax regimes remains a complex but necessary issue for future research and tax system design.