Along with other requirements for the OA visa. The real reason that the OA visa is liked by many is the fact that you never have to deposit 800,000 Thai baht in a Thai bank account in your name only. There are Americans who use the OA visa for 2 years then return to the USA and apply for a New OA visa for retirement.
Pardon me but it does have relevance. You must apply for any Thai Visa in the USA with the Thai Embassy or Consulate which services the STATE where you live in the USA.
It's likely that you also could use those assets you NOW have in your home country to obtain the OA visa for retirement. It's a one year Visa AND can be extended a second year. No funds needed in a Thai bank account. Explore the opportunity by looking at your home country Thai Embassy or Consulate for the OA visa requirements.