Which U.S. tax on corporate income was created by the Revenue Act of 1909?

The Revenue Act of 1909 created a U.S. corporate excise tax on the income of corporations.

President William Howard Taft supported the measure as part of a broader response to federal revenue pressures. Rather than describing itself simply as an income tax, the law imposed an excise tax measured by a corporation’s net income. This wording was politically and constitutionally important because the federal income-tax amendment had not yet been ratified.

The Supreme Court had struck down an earlier federal income tax in Pollock v. Farmers’ Loan & Trust Co. in 1895. The corporate excise tax was designed partly to avoid the constitutional problems raised by that decision. The Sixteenth Amendment was ratified in 1913, and a modern federal corporate income tax followed soon afterward.

The 1909 levy is therefore a bridge between nineteenth-century constitutional disputes and the modern U.S. income-tax system.