As long as you have the 500k thb in your account three months, then yes your other investments can support your application. If you mean you've got less than 500k thb and want to make up the different with investments, then no.
The ask:thailand community, consisting of multiple Q/A groups with over 100,000 members, powers this platform. It is not an official government resource. Our members actively contribute to this resource, and while we strive for accuracy, we cannot guarantee its complete reliability. Assistance to travelers is provided as a community service.