On 26 January 2011, the President announced the amended Income Tax Act incorporating the thin capitalization rule. Retroactively from 1 January 2011, if the ratio of a company's debts (to its related party) to its equity exceeds a certain ratio, the interest expense arising out of the portion of the debts exceeding said ratio is not deductible. However, banks, cooperatives, financial holding companies, bills finance companies, insurance companies, and securities firms are not subject to the thin capitalization rule.

The regulations concerning said thin capitalization rule, including the definition of related party, scope of debt and equity, debt-equity ratio and so on will be decided and announced by the Ministry of Finance.