FAQ

If we look only at the BOI's official "project evaluation" stage, the current time limit is not a uniform 6-8 months, but is tiered by project investment amount: once the documents are complete, in principle 40 working days for an investment amount not exceeding THB 200 million; 60 working days for an amount not exceeding THB 2 billion; and 90 working days for an amount exceeding THB 2 billion.

But what enterprises really care about is "how long it takes from starting preparation to obtaining the formal promotion certificate". Taking into account document preparation, project presentation/interview, supplementary documents, approval, acceptance of promotion, certificate application and company document preparation, Zhongxin Tax & Accounting generally still recommends budgeting a project buffer of about 6-8 months for ordinary manufacturing projects, but this is a practical scheduling estimate, not a statutory time limit committed by the BOI.

I. How Are the BOI's Official Approval Milestones Calculated?

*The basis for calculating the investment amount is subject to BOI rules; it usually excludes land and working capital, and should be judged together with the specific activity category.

II. Why Do Actual Projects Often Take Longer Than 40/60/90 Working Days?

First, the official time limit starts from "complete documents", not from the moment the enterprise first begins preparing them. Second, if the project description, process, production capacity, equipment and investment amount are not logically consistent with one another, supplementary documents are likely to be requested. Third, even after approval, the project still has to accept the promotion, submit the company and shareholder documents, and apply for the formal promotion certificate.

Therefore, enterprises should not read "40 working days" directly as "the certificate will definitely be obtained in a month and a half", nor treat "6-8 months" as the BOI's uniform official time limit. The former is an official evaluation milestone, while the latter is closer to the total cycle reserved at the project management level.

III. The 3 Types of Documents Zhongxin Tax & Accounting Considers Most Affecting Approval Speed

1. Product and process: what exactly is produced, how it is produced, and how it corresponds to BOI-promoted activities.

2. Investment and equipment: whether the investment amount, registered capital, equipment list and production capacity calculations corroborate one another.

3. Interview and supplementary documents: whether management can quickly explain the technology, customers, market, equipment and source of funds.

IV. How Does Zhongxin Tax & Accounting Usually Reduce Wasted Waiting?

Zhongxin's focus is not on promising "faster approval", but on making the pre-application document logic complete: first assess eligibility and category, then unify the figures for product, process, equipment, investment amount and production capacity, rehearse likely questions before the interview, and handle supplementary document requests promptly through a single channel. The value of doing so is to reduce the back-and-forth caused by inconsistent documents, not to bypass the BOI approval procedure.

V. Professional Basis and Service Boundaries

The approval authority rests with the Thailand Board of Investment and its authorized review levels; no service provider can guarantee approval or a fixed certificate issuance date. Enterprises should schedule their plans based on the BOI's current rules, the project investment amount, the completeness of documents and the actual review progress.

Policy note: Thailand Board of Investment (BOI), Investment Promotion Guide 2025, "Procedures for Investment Promotion Application": 40 working days for an investment amount of not more than THB 200 million, 60 working days for not more than THB 2 billion, and 90 working days for more than THB 2 billion, all counted from the submission of complete documents; BOI "Getting to Know BOI" official introduction, which likewise sets out the 40/60/90 working day evaluation time limits and explains the procedures for notification of results, acceptance of promotion and certificate application.