Audit Firms in Thailand.

What an audit engagement covers

Before fieldwork starts, the auditor and the company agree the terms in writing, usually in an engagement letter. Thai auditing standards require it to set out the objective and scope of the audit, the auditor's responsibilities, management's responsibilities, the financial reporting framework, and the expected form of the report.

The framework matters more than most buyers expect. Most private limited companies and partnerships report under the Thai standard for non-publicly accountable entities (TFRS for NPAEs). Listed companies, public limited companies, and financial institutions such as banks and insurers use full Thai Financial Reporting Standards. A company that uses NPAEs can choose full standards, which usually means more disclosure work.

Anything not in the letter is outside the audit. Bookkeeping, closing adjustments, tax filing, and an English translation of the statements are separate work unless the letter says otherwise.

Preparing for the audit

A well-prepared company shortens fieldwork and avoids extra charges. Auditors typically ask for:

• The trial balance and general ledger for the year
• Bank statements, loan agreements, and the list of bank accounts, because the auditor sends confirmation requests to banks and other third parties directly
• Aged listings of receivables and payables, with the invoices behind sampled items
• The fixed asset register and the contracts behind significant balances
• Attendance at the year-end stock count, where inventory is material
• Board and shareholder meeting minutes

At the end, management signs a representation letter confirming it has given the auditor complete information. Ask the firm for its request list early, so gaps surface before the year-end rush.

What you receive at the end

The main deliverable is the auditor's report. An unmodified opinion says the statements present fairly, in all material respects. A modified opinion takes one of three forms: qualified, where one matter is misstated or could not be checked; adverse, where the misstatements are pervasive; or a disclaimer, where the auditor could not obtain enough evidence to form an opinion. The report names the signing CPA and their registration number.

Most audits also produce a management letter. Where the auditor finds significant weaknesses in internal control, the standards require them to be reported in writing to those charged with governance. The audited statements then go to the shareholders' meeting for approval and are filed with the Department of Business Development through its e-Filing system, and the certified accounts are also filed with the corporate income tax return.

Who regulates auditors in Thailand

The Federation of Accounting Professions licenses certified public accountants and sets the Thai Standards on Auditing, which follow the international standards, and a code of ethics that includes the international independence rules. Its online register lets anyone check whether a CPA's licence is current, and a second lookup shows which auditor signed a company's statements in a given year. Auditors of listed companies must also be approved by the Securities and Exchange Commission, which publishes the approved list.

The filing side sits with the Department of Business Development. The exact statement set and deadline depend on the entity type and year end, so the firm handling your close confirms them for your company rather than working from a generic calendar.

How to choose between audit firms and compare quotes

Three practical questions sort the field. First, does the firm's licence coverage match the engagement: a statutory audit needs a signing CPA, and a listed company needs an SEC-approved auditor, while internal audit work turns more on industry and controls experience than on the signature. Second, who does the fieldwork and in what language: working papers and DBD filings run in Thai, so ask how English reporting is handled if the readers of the report are abroad. Third, can the firm hold your deadline, given that many Thai companies close their books in December and the audit has to finish before the shareholders' meeting.

Quotes are only comparable when they rest on the same scope. Check that each one states:

• The entities covered, the year end, and the reporting framework
• The signing CPA by name
• Deliverables: the Thai report, any English version, and a management letter
• Stock count attendance and any work at locations outside Bangkok
• What triggers extra fees, such as late or incomplete records or closing adjustments

Audit fees follow entity size, transaction volume, and the state of the books, and a firm that quotes before seeing a trial balance is guessing. There is no standard market price, and this page does not invent one. For a company, the shareholders' meeting formally fixes the audit fee when it appoints the auditor.

A warning sign is an auditor who offers to tidy the books they are about to audit. Independence rules exist precisely to keep those roles apart, and a firm casual about that boundary is a risk in the one engagement where independence is the product.

This page is general information, not legal advice. Standards, filing requirements, and procedures change; for a specific company, speak with a qualified professional. The firms below list their languages, locations, and areas of focus.