Prior to conducting business in Thailand, Americans should be familiar with the restrictions on foreign businesses in Thailand, especially the Alien Business Law (ABL). Because of the Treaty of Amity and Economic Relations, American companies operating under the Treaty are exempt from many of the restrictions on foreign investment imposed by ABL; however, being familiar with ABL and other restrictions is important. Also known as the National Executive Announcement No. 281 of 1972, ABL restricts the business activity of aliens or non-Thai residents. “Alien” and “alien business” is defined as a natural person or juristic person without Thai nationality. This includes a business with at least one-half of the registered capital held by aliens. The three categories of restrictions are as follows: Category A is completely closed to foreigners (with a few exceptions) doing business in certain sectors, most notably accounting, law and architecture. Category B is closed to foreigners unless promoted by the Board of Investment. Category B sectors include fishing, printing, tour agencies and other businesses. Category C requires an Alien Business License for retail, wholesale and other businesses. A complete list of restricted industries can be obtained upon request.While exempt from many of these regulations, American businesses are restricted from doing the following: Owning land Engaging in the business of inland communication Engaging in inland transportation and communication industries Engaging in fiduciary functions Engaging in banking involving depository functions Engaging in domestic trade in indigenous agricultural products Exploiting land or other natural resources