How to File PND 50 in Thailand: A Guide for Foreign Business Owners
If you own or direct a Thai limited company, PND 50 is one filing you need to understand. It is your company's annual corporate income tax return, due within 150 days of the end of your accounting period; for most companies with a December year-end, that means 31 May.
The good news is that the process is straightforward when you know what is involved and prepare in advance. Many foreign business owners have never actually seen their PND 50 or understood what goes into it. This guide changes that. We will walk you through the process, what your accountant needs from you, and how to avoid the most common mistakes.
What Is PND 50 and Why Does It Matter?
PND 50 (also written as ภ.ง.ด. 50) is the annual corporate income tax return filed with Thailand's Revenue Department. It reports your company's total revenue, allowable expenses, net profit, and the resulting corporate income tax liability for the full accounting year.
Every Thai registered company must file PND 50 - even if the company made no profit. Failure to file triggers automatic penalties regardless of whether any tax was actually owed.
PND 50 is not the only CIT filing your company needs to make. There is also PND 51, a mid-year estimate filed by the end of August (for December year-end companies). PND 51 estimates your profit for the first six months, and if your estimate falls short of actual profit by more than 25%, a surcharge of 20% applies on the shortfall. The two filings work together — PND 51 is the estimate, PND 50 is the final reconciliation.
How to File PND 50 in Thailand: What Your Accountant Needs From You
In practice, your accounting firm prepares and files PND 50 on your behalf. But they cannot do it without your cooperation - here is what needs to be in order before your filing can proceed.
Complete financial records for the full year. Every transaction — income, expenses, payroll, asset purchases — must be recorded and categorised. If your monthly bookkeeping has been maintained consistently throughout the year, this step is straightforward. If records have gaps, this is where delays begin.
An audited set of financial statements. Thai law requires that your annual financial statements are audited by a licensed Certified Public Accountant (CPA) before PND 50 is filed. The end-of-year audit produces the balance sheet, income statement, and notes that form the basis of the return. Your auditor and your bookkeeper need to be working from the same set of records.
Supporting documentation for deductions. Not every expense your company incurs is deductible for CIT purposes. Entertainment expenses, for example, are capped. Certain fines and penalties are non-deductible. Your accountant will classify expenses correctly, but they need proper documentation — receipts, invoices, contracts — to support each claim. The Revenue Department can request supporting evidence during an audit, and undocumented deductions will be disallowed.
Confirmation of any tax credits or incentives. If your company holds a BOI promotion, you may be entitled to a corporate tax exemption or reduction. These incentives must be correctly reflected in the return. Similarly, any withholding tax already deducted from payments received by your company during the year can be credited against your CIT liability. Your company's corporate Tax ID (TIN) is required for all filings with the Revenue Department.
CIT Rates and Your PND 50 Liability
Thailand's standard corporate income tax rate is 20% on net profit, though SME companies meeting certain capital and revenue thresholds benefit from reduced rate of 15% including a full exemption on the first 300,000 THB of net profit. The rate that applies to your company directly affects the figure on your PND 50 return. For a full breakdown of current rates, SME criteria, and how different company structures are treated, see our Corporate Income Tax service page.
Common PND 50 Mistakes Foreign Business Owners Make
After years of handling CIT filings for foreign-owned Thai companies, certain mistakes come up repeatedly:
Leaving everything to the last month. PND 50 requires audited financials. Audits take time. If you hand your accountant a year's worth of unreconciled records in April, the filing will be rushed, errors become more likely, and you may miss the May deadline entirely.
Underestimating PND 51. The mid-year estimate filed in August is not a formality. If your actual full-year profit exceeds your PND 51 estimate by more than 25%, the Revenue Department applies a 20% surcharge on the difference. Getting a reasonable estimate matters.
Confusing revenue with profit. CIT is assessed on net profit, not gross revenue. Your allowable deductions — salaries, rent, professional fees, depreciation, operating costs — reduce the figure substantially. Some business owners overpay because they do not claim legitimate expenses, and others underpay because they claim expenses that are not deductible.
Ignoring the DBD filing. PND 50 is filed with the Revenue Department. But your audited financial statements must also be filed separately with the Department of Business Development (DBD) within five months of your year-end. These are two different government departments with two different deadlines. Missing the DBD filing has its own penalties and can affect your company's good standing.
What Happens If You Miss the PND 50 Deadline?
The consequences are automatic:
- Late filing penalty: a fixed fine for submitting after the deadline
- Surcharge: 1.5% per month on any unpaid tax, calculated from the day after the deadline
- Compounding risk: if you also missed PND 51, penalties from both filings stack
For a company with even a modest tax liability, a few months of delay can result in penalties that exceed the cost of an annual accounting package.
How Attori Law Handles Corporate Tax Filing in Thailand
At Attori Law, we manage the full CIT cycle for foreign-owned companies - not just filing PND 50 in May, but the year-round preparation that makes it accurate. That means consistent monthly bookkeeping so your records are always current, coordinating your year-end audit with a licensed CPA, preparing your PND 51 mid-year estimate in August, and handling PND 50 preparation and e-filing by the May deadline. We also take care of the separate DBD financial statement filing that many business owners overlook.
Get in touch and we will assess where things stand. You can also view our full range of accounting and tax services to see how we support foreign businesses at every stage of the compliance calendar.
Frequently Asked Questions: Filing PND 50 in Thailand
Does my company need to file PND 50 if it made no profit?
Yes. Every registered Thai company must file PND 50 regardless of whether it earned a profit. A nil-profit return is still a legal requirement, and failure to file triggers the same penalties as a late profitable return.
What is the difference between PND 50 and PND 51?
PND 51 is a mid-year corporate income tax estimate filed within two months of the end of the first half of your accounting period — typically by the end of August for December year-end companies. PND 50 is the final annual return covering the full year, due within 150 days of your year-end. PND 51 is the estimate; PND 50 is the reconciliation.
Can my company have a non-December accounting year-end?
Yes. Thai companies can choose any 12-month accounting period. However, the most common — and administratively simplest — is a January to December year-end. If your company uses a different period, all CIT deadlines shift accordingly. Your accountant should confirm your specific dates.
How long do I need to keep financial records for CIT purposes?
Thai law requires companies to retain accounting records, supporting documents, and financial statements for a minimum of five years from the date of filing. The Revenue Department can audit any return within this period, so your documentation must be accessible throughout. We recommend keeping documents for 10 years in case they need to see more.
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