 All states require that foreign corporations register with the state before conducting business in the state.For U.S. federal tax purposes, where "foreign corporation" means a corporation that is not created or organized in the United States.For tax purposes, the Internal Revenue Service (IRS) treats all domestic companies in the same manner for tax purposes, without regard to where they were originally formed or organized within the Unites States, but applies different rules to companies that are formed or organized outside of the US.