Forty-five states impose a direct tax on corporations, measured at least partially by net income. Michigan, Nevada, South Dakota, Washington.
A state is empowered to tax any net corporate income attributable to in-state activity no matter where the corporation is headquartered. Corporations must apportion their income among the states where they have a sufficient connection (the legal term is nexus) and pay tax in each of those states. Several states tax unincorporated businesses separately.
