What is most commonly overlooked in filing forms PND.90 and PND.91?
Short answer
An individual present in Thailand for 180 days or more in a tax year is a Thai tax resident. Employment income earned in Thailand is taxable regardless of residence or of where it is paid, and the annual return is filed on PND.91 for employment income only or PND.90 where there are other categories.
How this case runs end to end
Determine residence by counting days, classify each income category, gather withholding certificates and allowance evidence, compute the liability with allowances and deductions, file PND.90 or PND.91 by the deadline, and keep evidence of any foreign tax credited.
Stage-by-stage timeline
| Stage | Work | Owner | Window |
|---|---|---|---|
| Filing | Submit through e-Filing or at the counter and retain the receipt | IVC | By the statutory deadline |
| Follow-up | Respond to any enquiry and archive the supporting file | IVC | As required |
| Scoping | Review the entity, period, filings due and current records | IVC | On enquiry |
| Document collection | Collect source documents, prior returns and statements | Client | 2–5 working days |
| Preparation | Bookkeeping, computation and reconciliation to the ledger | IVC | Depends on volume |
| Review | Client review of the computation and the return before filing | Client and IVC | 1–3 working days |
What to prepare
- Company affidavit, VAT certificate (PP.20) where issued, and the tax ID
- The accounting period and the filing deadline that applies to it
- Source documents: invoices, receipts, contracts and bank statements for the period
- Prior-period returns and the audited financial statements already filed
- Details of the authorised signatory and any e-Filing credentials in use
- For cross-border items: the counterparty's country and tax residence evidence
- A written authorisation where an agent files on the company's behalf
What "What is most commonly overlooked in filing forms PND.90 and PND.91?" actually involves
This question sits within personal income tax for individuals and foreign nationals. The authority or standard that governs it directly is the Revenue Department, under the personal income tax provisions of the Revenue Code, and every case is assessed against the rules in force on the day of submission. IVC prepares the file, checks internal consistency and coordinates with the receiving office; we are not a government body and we never guarantee how an authority will decide.
A double tax agreement can relieve double taxation but has to be applied with residence evidence rather than assumed.
Employment income for work performed in Thailand is taxable in Thailand even when it is paid into an overseas account.
Foreign-sourced income remitted by a Thai tax resident is assessed under the rules in force for the year concerned, so the remittance date matters.
Rules and requirements to settle before you start
Residence is decided by days present in the calendar year, not by visa type or work permit status.
Allowances and deductions must be evidenced; the deduction is disallowed on review where the supporting document is missing.
A nil month still requires a PP.30 filing; skipping it creates a late-filing record rather than nothing at all.
Input and output VAT reports must reconcile to the return and to the general ledger for the same period.
The mistakes that cost the most time
The most expensive pattern is treating the deadline as the start of the work. Monthly VAT and withholding returns depend on documents that arrive from suppliers and customers, so a file assembled in the last three days is the file where a missing tax invoice becomes an irrecoverable input credit rather than a phone call.
The second is inconsistency between systems. The return, the input and output reports, the payroll register and the audited accounts are all read together on review, and a difference nobody can explain turns a routine desk check into a full enquiry covering earlier periods as well.
Why files are delayed or returned
- Residence assumed from visa status instead of counted in days
- Withholding certificates missing at filing time
- Deductions claimed without supporting evidence
- Foreign remittances documented after the fact rather than at the time
- Reports that do not reconcile to the filed return
- Input VAT claimed on non-creditable items
Key terms in personal income tax for individuals and foreign nationals
- Permanent establishment
- A taxable presence in a country as defined by the applicable treaty article.
- DBD e-Filing
- The Department of Business Development system for submitting financial statements.
- Certificate of residence
- Evidence from a tax authority that a person or company is resident there for treaty purposes.
- Tax residence
- Status arising from presence in Thailand for 180 days or more in a calendar year.
- Input / output VAT
- VAT paid on purchases and charged on sales; the difference is remitted or carried forward.
- Section 50 bis certificate
- The withholding tax certificate the payer issues to the payee at the time of payment.
- PND.50 / PND.51
- The annual and half-year corporate income tax returns.
Official sources
- The Revenue Department (Thailand) — Tax registration, returns and e-Filing
- Department of Business Development — Financial statement submission (e-Filing)
- Social Security Office (Thailand) — Employer registration and contributions
- Thailand Board of Investment — Investment promotion and tax privileges
- Electronic Transactions Development Agency — e-Tax Invoice and e-Receipt standards
Scope and limitations
IVC provides accounting, tax compliance and document services as a private firm. This page is general information, not a case-specific tax opinion, and it is not issued by the Revenue Department or any other authority. Rules and deadlines change, so confirm the position for your own period before acting. Fees are quoted after scoping — please contact our staff by phone, LINE or email.
Information as of August 2026
Other questions in this group
- What documents are required for personal income tax for foreigners working in Thailand?
- What is the step-by-step process for personal income tax for foreigners working in Thailand?
- How long does personal income tax for foreigners working in Thailand normally take?
- Which authority handles personal income tax for foreigners working in Thailand?
- What conditions must be met before personal income tax for foreigners working in Thailand?
- Why is personal income tax for foreigners working in Thailand most often rejected or returned?
- How far in advance should personal income tax for foreigners working in Thailand be arranged?
- Can someone else act on your behalf for personal income tax for foreigners working in Thailand, and what power of attorney is needed?
- What is most commonly overlooked in personal income tax for foreigners working in Thailand?
- Does personal income tax for foreigners working in Thailand require additional translation or certification?
- What happens if a document for personal income tax for foreigners working in Thailand is lost or expired?
- How does personal income tax for foreigners working in Thailand differ for foreign nationals compared with Thai nationals?
Practical playbook: Accounting, Tax and Payroll in Thailand
A Thai company files monthly and annual returns on fixed statutory deadlines. The work is driven by the calendar: VAT and withholding tax each month, social security each month, audited financial statements and the corporate income tax return each year.
Documents to prepare
- Company affidavit, VAT certificate (Phor.Phor.20) and tax ID
- Sales and purchase tax invoices for the period, with receipts
- Bank statements for every company account
- Payroll register, employment contracts and social security registrations
- Prior-year audited financial statements and tax filings
Steps and method
1. Scope and system setup
Map the chart of accounts, VAT status, withholding categories and payroll cycle to the company's actual transactions.
Typical timeframe: 1–5 business days
2. Monthly bookkeeping
Record transactions, reconcile bank accounts and prepare withholding tax certificates for suppliers.
Typical timeframe: Monthly cycle
3. Monthly filings
File withholding tax (PND.3/53/54), VAT (PP.30/PP.36) and social security contributions within their statutory deadlines.
Typical timeframe: Monthly, by the filing deadline
4. Year-end close and audit
Prepare financial statements, work with the licensed auditor, then file with DBD and the Revenue Department (PND.50 and the half-year PND.51).
Typical timeframe: Annual cycle
Consultant tips
- Keep original tax invoices — an input VAT claim depends on a compliant tax invoice, not on the payment record alone.
- Issue withholding tax certificates at the time of payment; suppliers need them to claim their credit.
- Tell your accountant before a transaction is unusual (related-party, cross-border, share transfer) rather than after it is booked.
Pitfalls to avoid
- Late filing exposes the company to surcharges and penalties applied per return, even when tax is nil.
- Registering for VAT is mandatory once the turnover threshold is passed; waiting for a Revenue Department notice is not an option.
- Cash-basis records without supporting documents will not survive a Revenue Department review.
Official references
If you would rather not handle the paperwork yourself, the iVC team can run the whole file end to end — document review, translation, certification, submission and follow-up. Contact us by LINE @iVisa or call +66 80-557-8887 so we can assess your case before any work starts.
In-house accountant vs outsourced accounting firm
The difference is continuity, who owns the filing deadlines, and access to a licensed auditor.
| Aspect | In-house accountant | Outsourced firm |
|---|---|---|
| Scope | Day-to-day work as assigned | Monthly and annual closing and filing on the tax calendar |
| Continuity | Stops when the employee leaves | Backup staff and handover procedures |
| Specialist depth | Depends on the individual's experience | Registered bookkeepers plus coordination with a licensed auditor |
| Watch out for | Backlogs build up with no second reviewer | Documents must reach the firm each cycle or filings slip |
Doing it yourself vs having iVC manage the whole process
Both routes are valid. They differ in the time you spend, the risk of documents being returned, and whether an adviser reviews everything before submission.
| Aspect | Do it yourself | Managed by iVC |
|---|---|---|
| Pre-submission review | You check against the agency's published requirements | An adviser checks each document against the destination's rules first |
| Your time | You travel, queue and follow up yourself | We file and follow up; you receive progress updates |
| Rejection risk | Common causes: name spelling mismatch, expired documents, wrong certification order | We check the usual rejection triggers at source and fix them first |
| Specialist knowledge | You research each agency's rules yourself | A team with 15+ years of casework advises throughout |
| If something goes wrong | You restart the steps yourself | We assess the options and plan the fix immediately |
We work as advisers, not just a document courier
More than 15 years of casework (since 2011) in translation, certification and visa document preparation shows us the patterns behind repeated rejections, so we plan around them from the start.
- Case assessment first
- We review the profile, destination country and receiving authority before recommending a certification route.
- A document plan per person
- We sequence what must be re-issued, translated first, and certified in which order.
- Risks flagged early
- We point out the usual rejection triggers, such as name spelling that differs from the passport or document age limits.
- Follow-through to the end
- Regular progress updates, and immediate options if the authority requests more documents.
- Advice after completion
- The same set is often reused in the next step; we check whether it still qualifies or needs re-issuing.
If you would rather not chase each step yourself, send the case details for an assessment first, then decide.
Need an answer for your own case? Talk to our staff by phone, LINE or email.