ผู้สอบบัญชีกับสำนักงานบัญชี ต่างกันอย่างไรAuditor vs Accounting Firm in Thailand: Who Does What

Many business owners deal with both an accounting firm and an auditor during the year-end close, but the two roles are not the same. Understanding who is responsible for what helps you send information to the right party, plan the work sensibly, and avoid expecting either side to do work that falls outside its scope.

The distinction to grasp from the start

An accounting firm records business transactions, maintains the books, and prepares financial statements within the scope agreed with the company. An auditor examines the financial statements and the supporting evidence, then expresses an opinion in the auditor's report on whether the financial statements have been prepared in accordance with the applicable financial reporting framework.

Put simply, the accounting firm helps "prepare the information", while the auditor "examines it and gives an opinion". The Federation of Accounting Professions (TFAC) explains the difference between a bookkeeper and an auditor along the same lines. See the guidance from the Federation of Accounting Professions

That said, responsibility for the financial statements remains with the company's management. Engaging an accounting firm or an auditor does not transfer the company's duty to provide information, approve transactions, assess risk, and maintain internal control.

Who is responsible for what

An accounting firm may help prepare and file tax returns, but that does not mean accounting treatment and tax treatment follow the same rules in every case. An auditor may propose audit adjustments based on findings, but management must consider and approve them — the auditor does not make those decisions on the company's behalf.

How the two roles connect

Generally, the company sends documents to the accounting firm to record transactions and perform reconciliations. At period end, the accounting firm prepares the trial balance, sub-ledger reports, and draft financial statements. Management should review these for completeness before passing them to the auditor.

The auditor plans the work based on risk, selects samples, examines documents or obtains evidence from third parties, and discusses items that may need correction. If the company accepts the audit adjustments, the accounting firm then updates the books and returns a revised set of information. The process runs more smoothly when everyone works from the same version of the information and a clear point of contact is assigned.

Auditors must maintain independence and objectivity. They should therefore not take on decision-making responsibilities that belong to management, or perform work that would put them in the position of auditing their own output without appropriate safeguards. Whether the same provider can perform other work alongside the audit depends on the nature of the work, the level of risk, and the ethical requirements — it should not be decided on the name of the firm alone. See the Code of Ethics for Professional Accountants

Common misconceptions

• "Once the documents have gone to the accounting firm, the company is no longer responsible": management still has to confirm that the information is complete, accurate, and reflects actual transactions.
• "The auditor should fix the books": the auditor examines and communicates observations; the company and its bookkeeper are the ones who make and approve the corrections.
• "If the tax filings are complete, the financial statements must be correct": tax and financial reporting have different purposes and rules, and must be looked at separately.
• "The auditor checks every transaction": an audit uses risk assessment and sampling to obtain reasonable assurance. It is not a guarantee that every error will be detected.
• "It's enough to talk to the auditor after the books are closed": matters such as inventory counts, a new system, loans, transactions with companies in the group, or transactions that have never occurred before are better discussed in advance.

Checklist for dividing responsibilities clearly

• Set out the accounting firm's scope of work in writing
• Check the qualifications of the bookkeeper and the licensed CPA
• Specify who prepares, who reviews, and who approves each set of information
• Set the dates for delivering the trial balance, sub-ledger reports, and supporting documents
• Inform both parties of significant or unusual transactions
• Keep accounting, tax, and audit matters separate from one another
• Have management review the financial statements before signing
• Assess independence where one provider performs several types of work

If you are unsure which work should go to the accounting firm and which needs to be discussed with the auditor, agree on the scope and the responsible parties from the outset, so that the accounting, tax, and audit work connect properly.