Capital markets (ṣukūk, takāful)

The classical ʿaqd binds two parties. Capital markets bind many: a thousand certificate-holders, a community of mutual insureds. These two classes are the first to use the pool primitive, a set of participants whose shares total the whole, distributed pro-rata. The fiqh line they hold is the one that separates an investment from a bond, and mutual protection from gambling. Return must come from a real asset or a donated fund, the holder must bear the risk, and no fixed coupon may be guaranteed.

Note

Citations are [scholar-verify]; the engine proves consistency, not a fatwa.

Ṣukūk (sukuk)

Investment certificates. Each ṣakk is an undivided ownership share in a real asset (or usufruct, or venture), not a debt. The holder’s return is the asset’s rental or profit, distributed pro-rata, and the holder bears the asset’s risk. A ṣukūk that guarantees the principal plus a fixed return is a bond, which is riba, not ṣukūk (AAOIFI SS No. 17).

Code	What it guards
SUKUK-1	returns { income { basis; distribution } } present.
SUKUK-2	income is distributed pro-rata to holders’ ownership shares.
POOL-1 / POOL-2	the holder pool’s shares total 10000 bps, with at least two holders.

sukuk.fiqh: consistent

pool {
  holderA: 5000 bps;
  holderB: 3000 bps;
  holderC: 2000 bps;
}
returns {
  income {
    basis:        asset_rental;  // the return is the asset's rental, not interest
    distribution: pro_rata;      // by each holder's ownership share
  }
}
lifecycle { issue; distributeIncome; }

Takāful (takaful)

Cooperative protection (taʿāwunī). The participants form a pool and donate (tabarruʿ) into a mutual fund; claims are paid from it, and the surplus belongs to the participants, pro-rata. This is not commercial insurance, which sells risk-cover for a premium-for-profit and combines gharar, maysir, and riba, held impermissible by the OIC Fiqh Academy and AAOIFI. The difference lies in the basis of the contribution and the home of the surplus.

Code	What it guards
TAKAFUL-1	returns { contribution { basis; surplus } } present.
TAKAFUL-2	the surplus belongs to the participants, not the operator’s profit.
POOL-1 / POOL-2	the participant pool’s shares total 10000 bps, with at least two participants.

takaful.fiqh: consistent

pool {
  participantA: 4000 bps;
  participantB: 3500 bps;
  participantC: 2500 bps;
}
returns {
  contribution {
    basis:   tabarru;          // donation, not a profit-premium
    surplus: to_participants;  // surplus returns to participants, not the operator
  }
}
lifecycle { contribute; payClaim; distributeSurplus; }

Both classes lower the pool to an on-chain address[] holders and a parallel uint16[] sharesBps, with a constructor guard that the shares sum to 10000, and a pro-rata distribution loop. It is the same arithmetic the farāʾiḍ engine uses for inheritance. See The multilateral pool.