The Foreign Business Act of 1999 regulates the business activity of foreign nationals and foreign business entities in Thailand. 

Foreign business entities are defined as juristic persons in which more than half of the shares are held by foreign nationals.  These entities are restricted from certain industries reserved for Thai persons and juristic persons. This measure closed the loophole used by many foreigners to own less than half of the shares of a company while still effectively controlling the company with majority voting rights.

The Foreign Business Act divides industries restricted to foreigners into three lists.  List One businesses are restricted for "special reasons" and include media, fishery, forestry, rice farming and land trading.  List Two businesses are restricted to foreigners because they are related to arts and culture, natural resources and folk crafts.  List Three businesses, including the liberal professions, are restricted to foreigners because Thai nationals are deemed not yet ready to compete.