food belonging to someone else, or plantings and buildings on another person’s land, which the landowner may acquire at their fair market value, but not for more. There are many similar examples. The same applies to the extension of manumission to the remaining shares in a slave, as the Prophet (peace and blessings be upon him) said:

“Whoever frees his share in a slave and has enough wealth to cover the slave’s price must have the slave fairly valued, neither undervalued nor overvalued. He must then pay his co-owners their shares, and the slave is freed at his expense. Otherwise, only the share he has freed is free.”

Likewise, anyone obliged to purchase something for an act of worship—such as equipment for Hajj, a slave to be freed, or water for ritual purification—must purchase it at its fair market value. He may not insist on buying only at a price of his own choosing.

The same applies to the food or clothing he must provide for those whose maintenance is his responsibility. If food or clothing customarily considered suitable for them is available at its fair market price, he may not resort to something inferior while waiting for the suitable item to be offered to him at a price of his own choosing. There are many similar examples.

For this reason, a number of scholars, including Abū Hanīfah and his companions, prohibited those who divide real estate and other property for a fee from forming partnerships when people need their services and their fees would thereby rise. It is therefore all the more justified to prohibit sellers from colluding to sell only at a price they have fixed. Likewise, if buyers collude to join forces and share in whatever any one of them purchases in order to depress the prices of people’s goods, prohibiting them is also all the more justified.