What is the ruling on selling poultry feed at the future stock exchange price with an upfront payment and later delivery, with the client specifying the pricing day, or selling at a pre-determined price with the full amount paid in advance?

For a sale to be valid, the price must be known. Therefore, it is not permissible to link it to a future stock market price, due to the ambiguity of the price. The Messenger of Allah, peace and blessings be upon him, forbade sales involving gharar (excessive uncertainty). However, determining the price at the time of the contract is a valid form. The aforementioned transaction falls under the contract of Istisna’ (manufacturing contract), and many scholars have permitted the price therein to be deferred or paid in installments.