Comparing US GDP to the sum of standard measures of payments to labour and imputations of payments to capital results in a large and volatile residual term. Using US data, this column argues that this ‘factorless income’ does not entirely reflect economic profits or unmeasured investment flows. Instead, it likely emerges due to a gap between the cost of capital that firms actually face and the Treasury yields typically used to calculate capital rental rates. These results are important for policy and for understanding historical macroeconomic trends.