Deemed substantial interest defines ownership thresholds for business control affecting GAAR application and tax attribution. Defines deemed substantial interest for Chapter X-A (General anti-avoidance rule). A person is treated as having a substantial interest where, during the financial year, they are the beneficial owner of equity shares conferring a qualifying proportion of voting power in a company, or, in non-corporate businesses, are beneficially entitled to a qualifying proportion of the profits of the business.