Article 12 mandates that financial accounts accompanying tax returns must be prepared using the accrual basis of accounting. These accounts must adhere to International Accounting Standards (IAS) or other criteria specified by the Chairman of the Tax Authority. While the accrual basis is the default standard, the Authority may permit a taxpayer to use an alternative accounting basis upon request, provided it does not compromise the standards established by the Chairman. This ensures transparency, consistency, and alignment with global financial reporting practices for tax assessment purposes in Oman.