Muwatta 1954

Malik says: if a man sells goods that cost him one hundred dinars, reckoning eleven for ten, then later comes and says that they cost him ninety dinars, and the goods have been lost, the seller is given the choice. If he wishes, he takes the value of his goods on the day he received it, unless that value is more than the price at which the sale was first due, in which case he has no more than that, which is one hundred dinars and ten dinars. If he wishes, a quarter is deducted from the ninety, unless the price the goods reached is less than the value, in which case he is given the choice between what his goods reached, and his capital and profit, which is ninety-nine dinars. ¹

Belongs to the Muwatta, Book of Sales. Source: the Muwatta. Mentions Malik ibn Anas. Built on in the chapters on resale at cost plus profit (murabaha).