Several banks are offering fixed deposit plans where the interest rate increases in steps. For simplicity, assume that you have 1,000,000 baht in the K-bank plan.
Months 1-4, annual interest rate 1.75%:
interest earned during that period = 5,833 baht, net after 15% tax withholding = 4,958 baht.
Months 5-8, annual interest rate 2.25%:
interest earned during that period = 7,500 baht, net after 15% tax withholding = 6,375 baht.
Months 9-12, annual interest rate 3.75%:
interest earned during that period = 12,500 baht, net after 15% tax withholding = 10,625 baht.
Months 13-16, annual interest rate 6.0%:
interest earned during that period = 20,000 baht, net after 15% tax withholding = 17,000 baht.
TOTAL interest in 16 months after tax withholding = 38,958 baht. Effective interest rate = 2.92% per year.
A quicker way to get to the same number is (1.75 + 2.25 + 3.75 + 6.0)/4 = 3.44. After 15% tax withholding, 3.44% X .85 = 2.92%
Two questions:
1. Would you report this Thailand after tax income to the uncle in the U.S.?
2. In the U.S., withholding rate depends on the type of income, but the tax you pay depends on your total income from all sources, and therefore the tax withheld may be less or more than your tax due. Also, in the U.S., the interest and dividend paid to you are reported by the financial institution to you and the IRS; if you do not include that in your tax filing, you are automatically red-flagged by the computer. Do you know what the tax rules are that affect us in Thailand? Are you required to file if you have any interest income?







