Thailand accounting health check: 12 controls to test before problems become filings

An accounting health check is a controlled diagnostic, not an audit opinion and not a promise that every historical tax position is correct. Write down the entity, branches, bank accounts, registrations, accounting period and cutoff date. Decide whether the purpose is a routine control review, an accountant handover, annual closing or remediation after a missed filing.

Create a request list and an exception log before reviewing balances. For each gap capture the account, amount, period, evidence requested, responsible person and deadline. This turns a vague concern into a plan that a new provider, director or reviewer can continue. Companies in Bangkok can use the same handover scope when comparing a Bangkok accounting team with the current arrangement.

• Entity, branch and registration population confirmed.
• Opening and closing dates fixed for every ledger tested.
• Original exports retained read-only before adjustments.
• Materiality and escalation rules agreed in advance.

The core review covers: company and period master data; general-ledger continuity; bank and cash; revenue and receivables; purchases and payables; VAT; withholding tax; payroll and Social Security; inventory; fixed assets; loans, equity and related parties; and annual close and filings. Each area needs both a balance test and a document test. A zero balance is not evidence that the workflow operated correctly.

For example, agree every bank account to statements and explain old reconciling items; age receivables and payables to invoices and subsequent settlement; connect VAT reports to valid tax invoices; and trace loans or shareholder movements to agreements, approvals and bank flows. Growing companies should embed these owners in the wider startup and SME accounting routine instead of repeating a rescue review each year.

For each tax and payroll filing, perform two tests. First, start with the return and agree its bases, tax and payment to the ledger. Second, start with the ledger population and prove that all reportable transactions reached the appropriate return. The second direction catches omitted transactions that a return-to-ledger check cannot see.

Keep submitted forms, accepted acknowledgements and bank payment evidence together. The Revenue Department’s corporate-income-tax guidance states that PND.50 is due within 150 days from the accounting-period close and PND.51 within two months after the first six months; current forms and electronic instructions still need checking for the period. If the annual close is approaching, connect findings to the annual financial statements guide rather than treating the health check as the filing itself.

The company should be able to retrieve its books and evidence independently of a departing provider. Obtain ledger and trial-balance exports, journal detail, masters, reconciliations, filing receipts, working schedules, document indexes, portal ownership details and a list of unresolved matters. Do not accept a closing trial balance as a substitute for the transaction history needed to reproduce it.

DBD guidance on the Accounting Act explains that accounting books and supporting documents have prescribed custody and storage rules; moving records to another location may require the applicable permission, and known loss or damage has a notification process. Revenue Code section 87/3 separately requires VAT reports, invoices and supporting documents to be retained for at least five years and allows a longer period in specified circumstances. Confirm the rule for the company’s records before relocating or destroying anything.

• Native ledger and master-data exports open successfully.
• Every filing receipt is mapped to the relevant return and payment.
• Company-controlled access and recovery routes are documented.
• Physical and electronic document locations are recorded.

Historical cleanup can consume the team and make the next return late. Protect the current month with a clean cutoff, named owners and a documented opening position while older exceptions are investigated in a separate queue. Do not silently overwrite prior journals or documents; preserve the original, correction basis, approval and affected return.

Rank issues by imminent deadline, potential tax or reporting effect, value, recurrence and missing evidence. Payroll gaps should be routed through the 2026 payroll compliance checklist because employee changes, PND.1, Social Security, bank payments and ledger entries need their own connected trail.

The output should not be a single percentage. Provide a scope statement, evidence received, reconciliations completed, exceptions, untested areas and a prioritized action list. Distinguish confirmed errors from missing evidence and open questions. Show the affected period and value wherever possible, and identify which conclusions rely on management representations.

Use the report to make one decision at a time: stabilize the next filing, recover missing records, correct the ledger, seek tax advice or complete the provider handover. Send the accounting file for an initial review with the company name, accounting period, latest trial balance, filing list and the reason for the check; sensitive documents should then move through the agreed secure channel.