Article 36 establishes an exception to the valuation rules in Articles 34, 35, and 37 for transactions involving related parties. It stipulates that the value of a supply or import of goods or services between such parties shall be considered its market value if two specific conditions are met concurrently. The first condition is that the declared value of the supply is less than its market value. The second is that the recipient of the goods or services is not entitled to recover the full input tax that would have been charged. This provision ensures anti-avoidance by revaluing undervalued related-party transactions.