What ownership and trade advantages do Americans have in Thailand?

I was "unreliably" told that they can 100% own a Thai Biz.

Partially true.

What you're referring to is a Treaty of Amity corporation which is a result of a trade treaty with the United States. But don't get too excited. They're much more expensive to run, and they don't let you buy property as some quickly assume.

Most Americans in Thailand still open standard corporations with partial Thai ownership, even given the Treaty of Amity option.

Not interested in buying property in Thailand.

Any ideas on the extra cost involved ?

You will find some information here:

http://www.siam-legal.com//Business-in-Thailand/US-Thai%20Amity.php?gclid=CMC5n8Ctzr0CFVh6vQodaoAAeQ

What if you are not an American citizen but own an American company?

Can that company operate as an American ?

The biggest so-called advantage is that an American can own 51% of the company whereas the rest of the world can own 49%. I'm not so sure how much of an "advantage" that is.

In both cases the individual will still be putting up 100% of the money but only owning either 51 or 49 percent of their company. Would you do that in your own country?