Last updated on July 23, 2026
The US-Thailand Treaty of Amity and Economic Relations is the single biggest advantage an American investor has in Thailand. Signed on 29 May 1966 and in force since 1968, it lets US citizens and US-majority-owned companies do something almost no other foreigner can: own up to 100% of a Thai company and be treated, for most business purposes, as if they were Thai. This page explains what the treaty gives you, the sectors it does not cover, and how to get certified.
What the Treaty Actually Gives You
Under the Foreign Business Act B.E. 2542 (1999), a company is foreign if 50% or more of its shares are held by non-Thais, and foreign majority ownership of most service and trading businesses is restricted. The Treaty of Amity overrides that for Americans. A qualifying US company receives national treatment: it may be up to 100% American-owned and may operate in most sectors without a Foreign Business Licence.
To qualify, the company must be majority American-owned and American-controlled. That means US citizens hold at least 51% of the shares and form the majority of the directors. A company owned through a chain of other companies can still qualify, but every layer has to trace back to US citizens or US-incorporated entities.
What the Treaty Does Not Cover: the Big Six
The treaty is broad but not unlimited. Six categories are excluded, and an American company gets no advantage in them:
- Communications
- Domestic transportation
- Fiduciary functions
- Banking involving depository functions
- The exploitation of land or other natural resources
- Domestic trade in indigenous agricultural products
There is also one hard limit that catches people out: the treaty does not let an American, or an American company, own land. Land ownership by foreigners is barred by Section 86 of the Land Code, and the Treaty of Amity does not change that. An Amity company can lease land, hold a registered usufruct or superficies, and own the building on the land, but not the land itself.
How to Get Certified
Amity status is not automatic. It runs in two stages:
- Certification from the US Commercial Service at the US Embassy in Bangkok. You submit the company’s registration documents and proof of the US ownership and control (shareholder lists, passports, and, for a corporate US shareholder, its certificate of incorporation). The Commercial Service issues a letter certifying the company is American.
- Application to the Department of Business Development (DBD) for a Foreign Business Certificate under the treaty, submitting the Commercial Service certification. Once granted, the company is registered as treaty-protected.
On minimum capital, the ordinary Foreign Business Act figures apply: at least 2 million THB for a business that is not otherwise restricted, and at least 3 million THB where the activity would need a Foreign Business Licence for a non-American.
Amity or BOI?
Americans sometimes ask whether to use the Treaty of Amity or apply for Board of Investment (BOI) promotion. They are different tools. The Treaty of Amity is the fastest way to 100% American ownership of an ordinary service or trading business, but it gives no tax break and does not help with land or work permits beyond the ordinary rules. BOI promotion is activity-specific and slower to obtain, but it adds corporate tax holidays, easier work permits, and in some cases the right to own land for the promoted project. For a straightforward consulting, trading, or service company, Amity is usually the right call. For manufacturing or a target BOI activity, BOI often wins. Some businesses use both.
How ThaiLawOnline Can Help
We handle the whole Amity process: forming the Thai company, preparing the ownership evidence, obtaining the US Commercial Service certification, and filing for the Foreign Business Certificate at the DBD. We also advise on the sensible structure where an American holds the business and land needs are met through a lease or usufruct rather than ownership. Our fixed fee to register a Thai company is 45,000 THB; the Amity certification is quoted on top depending on the ownership chain. See our legal fees page.
One practical warning from experience: the treaty protects genuine American ownership, not an American name on paper over a non-American business. If the real capital and control are not US, the certification will not hold up, and the exposure is the same as any other misrepresentation to the DBD. If you are American, use the treaty properly and it is one of the best deals in Thai corporate law. Contact us to start.
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