Arabic (ربا النساء), also known as riba al-naqd, is a subcategory of riba al-buyu, in which one of the countervalues (such as those of the same genus) is deferred (while the other was spot). It arises in cases where deferment of either countervalue occurs whilst it must have been delivered instantly (at the same time). For instance, the exchange of 50 grams of gold for another 50 grams of gold (same grade), with the former being spot while the latter being deferred (forward).

This type of riba involves no excess in one countervalue over the other, but it only arises due to deferment on one side of the transaction (i.e., time factor).