Is it permissible to enter into a contract of forward sale (salam) for goods not currently in existence?

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It is permissible to enter into a contract of salam even if the subject matter is not present at the time of the contract. This is permissible for things like selling dates in winter or any non-existent item, provided it will exist at the specified time of delivery. This view is held by Malik, Al-Shafi'i, Ishaq, and Ibn al-Mundhir. The evidence is the Prophet's command upon arriving in Medina where people were practicing salam in fruits for one or two years: Whoever enters into salam, let him do so with a known measure, known weight, for a known period. The Prophet did not mention the requirement of current existence; had it been a condition, he would have stated it, and he would have forbidden salam for two years, as that would necessitate the non-existence of the subject matter during the middle of the year. Furthermore, the item is established as a debt in the seller's liability and is typically found at its source location, making salam permissible, similar to existing goods.