Fair American Corporate Tax Act or FACT Act - Amends the Internal Revenue Code to: (1) decrease from 35% to 28% the top marginal income tax rate for corporations (including personal service corporations); and (2) provide that the amount of any tax withholding for deductible payments made by a U.S. subsidiary of a foreign parent corporation to a related subsidiary in any country that has a tax treaty with the United States shall not be less than the amount which would be imposed if the payment were made directly to the foreign parent corporation.