Job Recruitment Website - Immigration policy - Why should American immigrants explain the source of funds? Is there any reason?

Why should American immigrants explain the source of funds? Is there any reason?

Professional law firms are needed to issue asset source certification reports for investment immigrants. It is only necessary to prove the source of funds for the investment of $500,000, and all kinds of income sources, such as house mortgage, stock income, corporate profits, salary income and gifts, are recognized. If you need it, I have a friend who works in immigration.