Accounting for Foreign-Owned and BOI-Promoted Companies

When the shareholder is an overseas legal entity, the first question local accountants field is rarely about Thai law at all — it's why the profit reported up to the parent doesn't match the figure filed on the PND 50 return. The gap usually traces to items recognized differently under Thai standards than under the group's standard: bad debt provisioning, revenue recognition on long-term contracts, or depreciation rates applied to fixed assets. Without a written reconciliation schedule explaining every adjustment, central finance ends up asking for clarification every single quarter, burning time on both sides for no real reason.

Bilingual books mean more than translating account names into English; the chart of accounts structure has to map to the group's own code set from day one so consolidation happens automatically rather than through manual mapping every month. Many companies build the Thai chart around whatever is convenient for the local bookkeeper, then face a headache at year-end when the parent asks for a standardized report. Structuring the chart to serve both sides from the day of incorporation saves far more time than retrofitting it later.

Intercompany transactions draw closer Revenue Department scrutiny each year, particularly cross-border goods sold below market price, management fees charged without a contract defining the scope of work, and inter-affiliate loan interest set unusually high or low against market rates. The disclosure form filed alongside the annual financial statements attached for related-entity relationships is only the opening move of an examination — if pricing looks anomalous, the Department can request further support, which requires an arm's-length pricing policy and calculation method already prepared in advance, not built after the fact.

Withholding on outbound remittances is easy to get wrong because the rate depends simultaneously on income type and destination country. Royalties and interest are ordinarily withheld at a set Revenue Code rate, but where the recipient's country holds a double tax treaty with Thailand and the recipient files for treaty relief with a certificate of tax residency from home, the effective rate can be materially lower than assumed. Skipping that check before remitting leaves the parent carrying the full Thai withholding and then chasing a foreign tax credit at home, a process that takes far longer.

BOI-promoted entities carry a clear layer of accounting burden beyond an ordinary company: revenue and expense of the corporate-income-tax-exempt activity must be segregated from the non-promoted portion, including cases with a single production line split between promoted and non-promoted output. Shared cost allocation needs a consistent, explainable basis rather than a monthly guess, because an allocation ratio that swings without justification invites questions from both the auditor and BOI itself.

The annual report filed with BOI to preserve incentives is not simply a form populated from existing statements; it must align with the conditions on the specific promotion certificate — export ratio, domestic raw material usage, or a minimum investment value that must be maintained. If project-level accounts aren't designed to pull these figures directly, the accounting team ends up re-tracing source documents each time a filing deadline nears, risking both delay and inconsistent figures from one year to the next.

Auditors reviewing a foreign-owned entity's statements typically request more supporting material than they would for an ordinary Thai company, since they must explain related-party relationships, the source of capital, and compliance with BOI conditions in the notes to the financial statements. Preparing working papers, asset registers and intercompany contract details ahead of fieldwork shortens the audit cycle and cuts down the back-and-forth, which matters greatly when the parent needs audited statements within the group's fixed deadline.

The real difficulty in foreign-owned company accounting isn't any single rule but coordinating several layers simultaneously: Thai and group standards running in parallel, transfer pricing files kept current year-round, outbound withholding correct on every remittance, and BOI reporting matching the certificate's conditions. Having a team that grasps the whole picture from incorporation onward reduces risk far more than patching problems one at a time as they surface.

Companies with multiple foreign shareholders arranged through complex structures, such as holding entities in a third country, often face Revenue Department questions about beneficial ownership whenever dividends or interest cross the border, since treaty relief typically requires the recipient to be the true beneficial owner rather than a mere conduit. Without documentation explaining the commercial rationale behind each layer of the shareholding structure, the Revenue Department can deny the reduced treaty rate and assess withholding at the full domestic rate instead. Preparing documentation on the group structure and the business rationale behind each ownership layer in advance meaningfully reduces this exposure.

BOI companies granted a corporate tax exemption capped by an investment ceiling must continuously track cumulative exempt profit against the approved limit, because once that ceiling is used up any profit beyond it becomes taxable at the normal rate immediately, with no advance warning from any authority. Companies without a real-time tracker for this cumulative figure commonly miscalculate tax in the year the exemption runs out, still treating the full profit as exempt the way it was the year before. Maintaining a quarterly tracking schedule against remaining projected profit for the year reveals ahead of time which year will actually start carrying a tax liability, allowing cash flow to be planned for it in time.

Temporarily transferring foreign staff between affiliated companies across borders to work in Thailand raises a personal income tax question distinct from the corporate tax picture, because an employee who becomes Thai tax resident beyond the statutory period owes tax on the full salary earned while working in Thailand regardless of which entity pays it, including any portion paid directly by the overseas parent. Many companies wrongly assume that if the Thai entity is not the one disbursing salary, no Thai tax obligation arises, which is incorrect under rules based on source of income and residency. The Thai entity's accounting team should track the residency clock for every transferred employee from their very first working day.