Taxable income is the sum of income used to compute a person's or a business's income tax due. Taxable income comprises salaries, pays, bonuses and tips, on top of investment revenue and unearned revenue. In this case, the corporation have $25 million that came from US Sources then the additional $10 million is also part of the taxable income because it is part of the normal course of the business. Therefore, GreenCo must report $35 million.