What is the difference between a conventional certificate and an Islamic sukuk certificate?

The Islamic certificate (sakk, plural sukuk) is based on the principle of Mudaraba (a profit-sharing investment partnership) or Wakala bil-Istithmar (investment agency), which is compliant with Sharia.

Its return is not fixed but variable, and it is paid on account (as an interim payment) until the final settlement is carried out based on the results of the bank's business.