Which authority handles the withholding tax certificate (Section 50 bis)?

How this case runs end to end

Classify the payment type, apply the correct rate, issue the withholding certificate on payment, file the monthly return by the deadline, and file the certificates with the accounting records for the payee's later credit claim.

Stage-by-stage timeline

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 "Which authority handles the withholding tax certificate (Section 50 bis)?" actually involves

This question sits within withholding tax. The authority or standard that governs it directly is the Revenue Department, under the withholding 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.

The withholding recorded by the payer and the credit claimed by the payee are cross-checked, so mismatched details invite enquiry.

The withholding certificate must be issued when payment is made, because the payee needs it to claim the credit in their own return.

Late remittance carries a surcharge calculated per month of delay, so a missed deadline is cheaper to correct immediately.

Rules and requirements to settle before you start

The rate follows the nature of the payment, not the label on the invoice; service, rent, transport and professional fees each have their own treatment.

Payments abroad are reported on PND.54 and may be reduced by a double tax agreement only when residence evidence is held.

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

• The wrong rate applied because the payment was classified by invoice wording
• No Section 50 bis certificate issued at the time of payment
• Treaty relief applied without residence evidence on file
• Certificate details that do not match the payee's tax ID
• Reports that do not reconcile to the filed return
• Input VAT claimed on non-creditable items

Key terms in withholding tax

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.

PP.30

The monthly VAT return, filed whether or not the period had activity.

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.

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