Thailand BOI certificate: the benefits and deadlines to read first

01What to read first on the certificate itself

A lot of owners breathe out on the day the promotion certificate arrives, put it in a drawer, and move on. That is the dangerous move. The certificate is not a licence that makes you tax-free from here on; it is a contract with dates in it, and next to every benefit sits a window that closes. In the first week, read the following passages word by word.

• The approved activity and scale. The exemption covers only the promoted activity as approved on the certificate. Moving the plant, expanding capacity, changing registered capital or the shareholding ratio all have to be reported to the BOI and approved before you act; changing any of them on your own breaks the promotion conditions.
• The exemption provisions. Look at the number of years of corporate income tax exemption and at the cap on it. For most tiers the total exemption is capped at 100% of the project investment, excluding land and working capital. Once the cap is used up you pay tax as normal, even if years remain on the clock.
• Project-specific conditions. Some certificates carry conditions of their own, such as a deadline to reach first revenue. Not every project has them. Do not go by what another company's certificate said — read your own, line by line.

02Two hard deadlines, both counted from the issue date

Two of the deadlines do more damage than the rest if you miss them, and both run from the same day.

• Duty-free machinery imports: 30 months. All machinery that is to come in free of duty has to be imported within 30 months of the issue date. Overrun and the exemption is gone; duty is payable in the ordinary way. There is a formal extension mechanism, but you have to apply for it yourself and in advance. Machinery for research and development or for environmental purposes is usually outside this limit.
• Start of operations: 36 months. Within 36 months of the issue date — the 30 months for machinery plus six — the project has to reach a state where it can open, and you have to apply for the operation licence. Being late here goes straight to your corporate income tax exemption.

The usual place people come off is the starting date. In practice a lot of companies count back by instinct from the approval date or from the date they accepted the promotion, and both of those fall earlier than the issue date. Use the wrong anchor and the margin you think you have is not there. Every countdown runs from the issue date printed on the certificate, and from nothing else.

03Two tracks: the benefit only saves money once it lands on the tax return

The corporate income tax exemption is not deducted automatically when the certificate takes effect. It takes one step at each end. At the BOI end you register that you are starting to use the exemption and reconcile the amount used against the amount remaining, year by year — that step reduces no tax at all. The tax is actually reduced at the other end, when the BOI exemption is reported correctly on the annual corporate income tax return (PND.50) filed with the Revenue Department. Leave it off and none of the quota on your certificate turns into tax saved.

The two ends also have to agree with each other. The first revenue date, the total cap and the quota used so far are three numbers that must match between the BOI record and the tax filing. Note in particular that the exemption years and the cap run from the date the promoted business first has revenue, not from the issue date of the certificate. Get that date wrong and the whole exemption timeline shifts. Which taxes you still pay under BOI.

04Count everything back into one calendar, and stop following the old wording

In the week the certificate arrives, take the issue date as the anchor and put everything on the same calendar: the 30 months, the 36 months, the quarterly progress report (due within 30 days of each quarter end, and filed even for a quarter in which nothing happened — you report zero progress), and the annual operating report each 31 July.

Watch out for old wording. Some older certificates and older reference material still print instructions to submit reports in February and July each year; newer announcements have superseded that. Following the old text to the letter produces missed filings as a matter of course — and one missed filing can lock the duty-free import of both machinery and raw materials. What has to be filed every year once you hold a certificate.

Every certificate carries a different combination of provisions, a different basis for the cap and different project-specific conditions, so the above is only a general map. Which deadlines are on your certificate, what day each one falls, and how best to use the exemption quota have to be checked line by line against the certificate itself, the approval documents and your accounts, and then counted back into a timetable of your own. These rules change often; check the latest official announcement before you act. What the BOI engagement covers.