This rule mandates the registration process with the Tax Department for entities involved in Kuwait's investment sector. It applies to investment fund managers, custodians, and incorporated bodies subject to the Kuwait Income Tax Decree who manage or invest in funds, portfolios, or directly in the Kuwait Stock Exchange. The rule specifies the information required on designated registration forms, such as entity details and contribution percentages, and mandates the submission of supporting documents like the memorandum of association. It also requires separate filings for Kuwaiti/Gulf and foreign bodies.