What are the requirements for the 400,000 THB security deposit for a Thai family extension of temporary stay?

For a Thai family extension of temporary stay, the requirement of a 400,000 THB security deposit can be met by maintaining a normal checking or savings account with this amount present for at least two months before applying. It is crucial to ensure the account is solely in the applicant's name and remains open until the visa application is processed, as authorities may ask for recent bank statements at the time of application.