Consideration of the collateral security structure⁴¹ is a critical factor; it needs to be the subject of legal opinions and is subject to Shari'a permissibility (in the case of perfectibility⁴²). Those security interests must be the first priority (there can be no prior or subsequent claims) and be perfected (or perfectible).

⁴¹ Collateral security structure is mainly used in Sukuk based on Shari'a-compliant project financing.

⁴² In legal terminology, perfection relates to the additional steps required to be taken in relation to a security interest in order to make it effective against third parties and/or to retain its effectiveness in the event of default by the grantor of the security interest.