The Classical Problem
Islamic contract law generally prohibits selling what you don’t yet own and haven’t yet made. Bay’ al-ma’dum (sale of the non-existent) is void as a category. Yet construction projects, custom manufactured goods, and bespoke items are fundamental economic needs. How can a Shari’ah-compliant economy build a ship that doesn’t yet exist?
The Hanafi school’s solution: istisnaa is not analyzed as a regular sale (because the object doesn’t exist) but as a unique contract type validated by the consensus of long-established commercial practice. The Prophet did not forbid it, and the community has practiced it continuously.
Conditions for Validity
For an istisnaa to be valid:
- Precise specifications: The manufactured item must be described in detail — material, size, design, quality. Vague descriptions create prohibitive gharar.
- Price agreed upfront: Unlike salam, the price in istisnaa does not need to be paid in advance; it can be paid in stages or at delivery.
- Manufactured goods: Istisnaa applies to things that need to be manufactured, not natural goods like agricultural products.
- No binding deadline by default: Classical Hanafi doctrine held that neither party was bound before delivery; either could withdraw before the item is made.
Parallel Istisnaa in Modern Finance
Contemporary Islamic finance uses parallel istisnaa: the bank commissions goods from a manufacturer (first istisnaa), then sells them to the ultimate buyer (second istisnaa). This enables large construction and infrastructure projects to be financed Islamically.
AAOIFI Shari’ah Standard 11 governs parallel istisnaa and requires that the two contracts be legally separate — the bank as intermediate party must bear real risk between them.
See also: Fiqh Al Gharar, Fiqh Al Madhab Al Maliki, Fiqh Al Madhab Al Hanbali, Fiqh Al Madhab Al Shafii, Ilm Al Usul