Starting in 2018, corporations pay a flat tax of 21% on all their profits. The 21% rate is lower than the top five individual income tax rates, which range from 22% to 37%. The benefit of the lower rates is largely lost due to double taxation if corporate profits are distributed to the shareholders, who must pay individual income tax on such dividends. However, many corporations want or need to retain some profits in the business at the end of the year -- for instance, to fund expansion and future growth. If it does, that money will be taxed only once, at the 21% corporate income tax rate. Thus, a corporation's owners can save money by keeping some profits in the company.