Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
Islam has set strict regulations for the exchange of "Ribawi" assets (items subject to usury rules) to maintain the stability of currency and transactions and to prevent the great evils resulting from Riba. The Prophet (peace be upon him) said: "Gold for gold, silver for silver, wheat for wheat, barley for barley, dates for dates, and salt for salt—like for like, equal for equal, and hand-to-hand. If these categories differ, then sell as you wish, provided it is hand-to-hand." [Narrated by Muslim].
Selling gold for gold requires both equal weight and immediate possession in the meeting of the contract. However, when selling gold for paper currency, only immediate possession (hand-to-hand exchange) at the time of the contract is required. Possession (Qabd) of gold is achieved through one of the following means:
1. Physical Possession: The buyer takes the gold bar themselves during the session.
2. Agency Possession: The buyer’s agent takes possession of the gold.
3. Specific Identification: Assigning the gold bar with unique serial numbers or distinguishing marks and enabling the buyer to dispose of it freely.
4. Ownership Certification: Receiving a certificate representing the ownership of a specific, distinguished gold bar, provided the certificate is issued on the day of the contract by legally recognized entities that empower the buyer to take physical delivery whenever they wish.
The first and second methods are agreed upon by classical jurists as Physical Possession (Al-Qabd al-Haqiqi). The third and fourth methods are known as Constructive Possession (Al-Qabd al-Hukmi). This has been permitted by the Sharia Board of the Accounting and Auditing Organization for Islamic Financial Institutions (AAOIFI). This is because holding a gold certificate with the described specifications is equivalent to physical possession in terms of legal effect, transfer of risk, and the ability to dispose of the asset—especially since gold bars today are often kept in licensed, regulated vaults. The entity managing the vault acts as an agent for the certificate holder in possessing and protecting the gold (See: AAOIFI Sharia Standard No. 57).
Many gold trading operations through speculation do not adhere to these guidelines, and such failure leads to financial crises.
Therefore: If the gold is possessed through any of the four means mentioned above, the transaction is Sharia-compliant. If these conditions are not met, the trading is prohibited.
Regarding selling the gold bar back to the same merchant: The general rule is that it should ideally be sold to someone else to avoid falling into ’Einah (a prohibited buy-back arrangement used to circumvent Riba). However, if the sale happens without any prior agreement or hidden intention to do so, there is no objection to selling it back to the same merchant at the new market price, provided the aforementioned conditions for a valid sale are met. And Allah the Almighty knows best.