Corporations are treated as a separate legal taxable entity for income tax purposes. Therefore, corporations pay tax on their earnings. If corporate earnings are distributed to shareholders in the form of dividends, the corporation does not receive the reasonable business expense deduction, and dividend income is taxed as regular income to the shareholders. Thus, to the extent that earnings are distributed to shareholders as dividends, there is a double tax on earnings at the corporate and shareholder level. S corporations and LLCs are pass-through entities that are not subject to the double tax.