When your Thai business has surplus cash and chooses to lend it to the directors or other companies in the group, it has to charge an interest. The tax officials will tell you to adjust your corporate income tax return to reflect the interest income from such lending. Usually they are fine with the rate of interest of not less than the interest the company will get if it deposits the money in a fixed account.

When the company receives interest income on the money lent to its directors and other companies, it has to file a Specific Business Tax Return (PT 40) and submit 3.3% on the interest received within 15th of the following month.

THAI ACCOUNTANT suggests you always accrue the interest income when you lend money to other people, but file the SBT form PT 40 only when you have received the interest money.