Accounting policies under income computation standards require substance over form, reasonable policy changes, and mandatory disclosure of material impacts. Income Computation and Disclosure Standard I applies to significant accounting policies used for computing income under business or other sources. It recognises going concern, consistency and accrual, but not materiality or prudence, and requires substance over legal form. Marked-to-market loss or expected loss is not recognised unless permitted by another ICDS. Accounting policies must present a true and fair view, changes require reasonable cause, and significant policies, material changes, expected future impacts and non-compliance with fundamental assumptions must be disclosed.