Accounting and Audit Requirements for Thai Companies

Every Thai limited company must, every year, even if dormant:

• keep books;
• have its financial statements audited by a Thai CPA;
• hold an AGM;
• file statements with the DBD;
• file a corporate tax return with the Revenue Department.

There is no small-company audit exemption for limited companies. Many foreign founders are surprised by that, and it is the most common source of fines.

1. Who does what#

Bookkeeper qualifications (DBD rules):

• Thai nationality;
• residence in Thailand;
• a vocational diploma in accounting at minimum for small entities (capital ≤5M, assets ≤30M, revenue ≤30M);
• a bachelor's degree in accounting for larger ones;
• continuing professional development each year.

2. Bookkeeping obligations#

• Start the books from the date of registration.
• Keep accounting documents that support each entry, such as invoices, receipts and contracts.
• Close accounts every 12 months. The first accounting period may be shorter.
• Record entries within the DBD's time limits. For example, cash entries must be made within 3 days of the transaction.
• Keep the books and supporting documents at the registered office for 5 years from the closing date. The DBD may order up to 7.
• Apply TFRS for NPAEs (most SMEs) or full TFRS (listed and public-interest entities).

3. The annual cycle (December year-end)#

Registered partnerships do not need an AGM. They must file financial statements within 5 months of year-end.

4. Penalties#

Since the Accounting Act amendment of B.E. 2565, most breaches are administrative fines (por pin-ai) imposed by the DBD rather than criminal fines.

Directors can be personally fined. Separately, the CCC fines late AGMs and late Bor Or Jor 5 filings. A company that has not filed for 3 consecutive years can be struck off by the DBD as defunct, though directors remain liable.

The RD's penalties apply separately:

• a 1.5% monthly surcharge on late tax;
• a penalty of up to 100% of the tax;
• a 2,000 THB fine for late filing.

5. What it costs in Bangkok#

Indicative 2026 market ranges, from published price lists of Bangkok accounting firms:

What drives the price:

• document volume;
• VAT registration;
• foreign-currency transactions;
• BOI conditions, including separate accounts for promoted activities;
• the state of the books when the firm takes over, since cleaning up a backlog is expensive.

6. Worked example: first year for a new company#

A company registered on 15 March 2026, with a December year-end:

1. March 2026. Appoint an outsourced bookkeeper. Books start 15 March. Register for VAT if needed, and file PND.1 and SSO each month once staff are hired.
2. August 2026. The first PND.51 is due only if the first period is longer than 6 months. Here it runs 15 March – 31 December, so a half-year estimate is due within 2 months of the first 6 months.
3. January–March 2027. Year-end close and CPA audit of the 9.5-month period.
4. By 30 April 2027. AGM. Bor Or Jor 5 filed within 14 days.
5. By 30 May 2027. DBD e-Filing and PND.50 (allow for e-filing extensions).

Budget: about 6,000 THB × 10 months for bookkeeping + 25,000 THB for the audit ≈ 85,000 THB in year 1.

7. Choosing an accountant: checklist#

• [ ] DBD-registered bookkeeper assigned to your file (ask for the name)
• [ ] Separate, independent CPA for the audit
• [ ] English reporting: monthly P&L, VAT and WHT summaries
• [ ] Cloud accounting (Xero, FlowAccount, PEAK, Express) or a scan-and-upload workflow
• [ ] Experience with your issues: BOI, FBL, transfer pricing, foreign shareholders
• [ ] Clear scope: what is included, and the price per extra document
• [ ] Deadlines calendar with reminders
• [ ] Hand-over terms if you leave

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8. Common problems#

• Dormant companies not filing. Even with zero activity you need books (or a formal dissolution), an audit, an AGM, DBD e-Filing and PND.50.
• Director loans not documented. Unexplained cash in or out causes audit qualifications and tax questions, including deemed interest under Revenue Code s.65 bis.
• Capital "paid" but not banked. The auditor checks paid-up capital against bank evidence.
• Lost tax invoices. Without valid tax invoices, input VAT and expenses can be disallowed.
• Switching accountants late in the year. The new firm must reconstruct records. Switch right after the annual filing.

9. Related-party transactions and transfer pricing#

Foreign-owned companies usually trade with their parent or sister companies (service fees, royalties, loans, purchases).

• Under Revenue Code s.71 bis–71 quater, a company with revenue of 200 million THB or more must file a transfer pricing disclosure form with PND.50, listing related-party transactions.
• On request, it must provide a TP report within the RD's deadline.
• Smaller companies are not required to file the form, but related-party prices must still be at arm's length.
• Document intercompany service fees with an agreement, invoices and evidence that the services were actually received. The RD regularly disallows unsupported "management fees".

Frequently asked questions#

Does a small or dormant Thai company need an audit? Yes. Every limited company needs an annual CPA audit, regardless of size or activity. Only small registered partnerships may use a Tax Auditor instead.

What is the deadline to file financial statements with the DBD? Within 1 month of the AGM, which itself must be within 4 months of year-end. For a December year-end, that is about 31 May.

What happens if I don't file? Administrative fines of up to 50,000 THB for non-submission, plus CCC fines and RD penalties. After repeated non-filing, the company risks being struck off.

Can a foreigner keep the books? No. The bookkeeper must be a Thai national registered with the DBD. Foreign staff can do management accounting.

Can I change my financial year-end? Yes, with Revenue Department approval. The first period after a change can be shorter than 12 months.

Do I need separate accounts for BOI-promoted activities? Yes. BOI-promoted and non-promoted income must be separated to claim the CIT exemption.

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Related guides#

• Corporate Income Tax in Thailand: Rates, SME Rates, Filing Deadlines
• VAT Registration in Thailand: The 1.8M THB Threshold, PP.30 Filing and Tax Invoices
• Payroll and Social Security in Thailand: Employer Guide
• How to Close a Company in Thailand: Dissolution and Liquidation Step by Step