Offshore derivative instruments and over-the-counter derivatives included in tax rule scope, extending applicability to specified derivative contracts. The amendment to rule 21AK adds offshore derivative instruments and over-the-counter derivatives to the rule's scope and substitutes the Explanation to define key terms: derivative, non-deliverable forward contract, offshore banking unit, offshore derivative instrument, over-the-counter derivatives, and permanent establishment, thereby clarifying the rule's applicability to these specified instruments and entities.