How to Prepare Your Business for an External Audit in Thailand
An external audit is easier, faster and less disruptive when your records are ready before the auditor arrives. This guide explains the key deadlines for Thai limited companies and gives you a practical checklist to work through before fieldwork begins.
Why preparation matters
Every Thai limited company must have its annual financial statements audited by a licensed auditor. Well-prepared records mean fewer follow-up questions, fewer adjustments and a timeline you can plan around. Poor preparation usually shows up as repeated document requests, last-minute corrections and pressure on your filing deadlines.
Know the key deadlines
Under the Department of Business Development (DBD) guidance for companies, the main year-end milestones are:
Close the accounts every 12 months; the first closing must be within 12 months of the date bookkeeping started.
Approve the audited financial statements at a shareholders’ meeting within four months of the closing date.
Submit the financial statements to the DBD within one month of shareholder approval.
File the shareholder list with the registrar no later than 14 days after the annual general meeting.
File the corporate income tax return (PND.50) within 150 days of the year-end, with the audited financial statements attached (158 days if filed online, according to the Revenue Department).
Work backwards from these dates. If the audit must be finished in time for an AGM within four months, your year-end closing usually needs to be done within the first several weeks after year-end.
Checklist: what to prepare before fieldwork
1. A closed and reviewed trial balance
Post all transactions for the year, record year-end accruals and prepayments, and review the trial balance for unusual balances before you send it to the auditor.
2. Bank and cash records
Bank statements for every account for all 12 months
Bank reconciliations at year-end, with explanations for reconciling items
Details of loans, overdrafts and any guarantees
3. Receivables, payables and inventory
Aged lists of customers and suppliers that agree to the general ledger
Explanations for long-outstanding balances
Inventory count sheets and the valuation method used, if you hold stock
4. Fixed assets
A fixed asset register that agrees to the ledger
Invoices for major additions and documents for disposals
Depreciation policies and calculations
5. Tax and statutory records
Monthly VAT and withholding tax returns with payment receipts
Social security filings
Minutes of directors’ and shareholders’ meetings
Copies of significant contracts, leases and loan agreements
Practical tips
Agree a timetable with your auditor early, including the date the trial balance will be ready.
Nominate one contact person who can answer questions and collect documents.
Explain unusual transactions in writing before fieldwork, such as large one-off sales, related-party transactions or new financing.
Keep documents organised by account, matching the order of your trial balance.
Example (illustrative only, not a client case): a trading company that reconciles its bank accounts and customer balances every month typically has far fewer year-end questions than one that reconciles only once a year, because differences are found and fixed while the details are still fresh.
How YP can help
Our Annual Financial Closing service prepares audit-ready financial statements and supporting schedules, and our Audit Services team carries out independent statutory audits under Thai Standards on Auditing. To protect auditor independence, the same firm should not both prepare and audit your financial statements; we will explain the options that fit your situation.
Planning your next year-end? Book a consultation and we will help you build a realistic timeline.
Sources
Information checked on 26 October 2026. This article is general information, not professional advice for your specific situation.
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