Hybrid mismatch arrangements exploit cross jurisdictional tax characterisation differences to secure duplicate deductions or non taxation. The primary recommended rule denies a payer's deduction to the extent a payment is not included in the recipient's taxable income in the counterparty jurisdiction or is also deductible there; if the primary rule is not applied, a defensive rule permits the counterparty jurisdiction to include the payment in income or deny the duplicate deduction depending on the mismatch type.