In 1993 there were about 52,000 foreign-controlled corporations in the United States, 19,000 foreign corporations with business activities in the United States, and an estimated 80,000 U.S.-controlled foreign corporations. GAO has previously reported on problems with international tax compliance and the fact that proportionately more foreign-controlled corporations pay no U.S. income taxes versus U.S.-controlled corporations. Congress and others have raised questions about the complexity of the international tax laws and about the Internal Revenue Service's (IRS) ability to ensure that corporations are accurately calculating their tax liabilities. Therefore, Congress authorized IRS more international resources for fiscal year 1994. This fact sheet provides information on (1) how IRS has used additional resources allocated to international compliance activities and (2) how IRS measures the effectiveness of these activities.