Revenue Department has issued guidance requiring companies and juristic partnerships to use Bank of Thailand exchange rates to convert foreign currency, assets and liabilities into Thai currency for calculating net profit subject to corporate income tax under Section 65 bis (5) of the Revenue Code, with the rules taking effect from the announcement issued on 7 July 2026.
The Thailand Revenue Department has issued a guidance, on 7 July 2026, outlining the method that companies and juristic partnerships must use to convert foreign currency, foreign currency-denominated assets, and liabilities into Thai currency when calculating net profit subject to corporate income tax under Section 65 bis (5) of the Revenue Code.
Companies or juristic partnerships that hold foreign currency, assets, or liabilities valued in foreign currency as of the last day of their accounting period must convert those amounts into Thai currency using exchange rates calculated by the Bank of Thailand as of the last day of the accounting period.
For companies or juristic partnerships other than commercial banks or other financial institutions prescribed by the Minister, two calculation methods are available. They may either use the average rate between the buying and selling rates of commercial banks as calculated by the Bank of Thailand, or calculate the value or price of foreign currency or assets using the average buying rate of commercial banks as calculated by the Bank of Thailand while valuing liabilities using the average selling rate.
The Revenue Department said that once a company or juristic partnership selects one of the permitted methods, it must continue to apply that method consistently unless approval to change the method is granted by the Director-General.
For commercial banks and other financial institutions prescribed by the Minister, the announcement requires the use of the average rate between the buying and selling rates of commercial banks as calculated by the Bank of Thailand when converting the value or price of foreign currency, assets, or liabilities into Thai currency.
The guidance also specifies that companies or juristic partnerships using the average buying rate to value foreign currency or assets must apply either the bill buying rate or the telegraphic transfer buying rate, in accordance with generally accepted accounting practices.
Where the last day of an accounting period falls on a Bank of Thailand holiday, companies or juristic partnerships must instead use the exchange rate calculated by the Bank of Thailand on the last business day preceding the holiday.
