However, this equilibrium could be disturbed, for instance, by hoarding, meeting the rider on his way to the market (talaqqi al-rukban),18 monopolies, underselling, and collusion among otherwise competitive firms. These practices allow market players to manipulate prices and introduce a degree of artificiality into the market. They act as hindrances to the natural functioning of the market, distort the existing equilibrium and spoil markets.
Interference is therefore necessitated in order to stop interferences and restore the balance to the market. In this way, it is argued, the true meaning and spirit of the hadith is upheld. Muslim jurists have also accepted the possibility of interference in the market in these situations under the doctrine of necessity and public interest. Indeed the institution of hisbah19 was established to prevent these hindrances to the natural functioning of the market.
The muhtasib was responsible for supervising markets and common morals. Among his duties were to check irregularities and to ensure that market players were on the right track and In the Hadith, the prophet forbids an operation called «talaqi al rukban». It refers to a salesman who buys goods on the borderline of a market for a lower price then sells at the market price trying to take advantage of the ignorance of the buyer.
Talaqqi al-rukban is part of ghabn, which is object buy-sell at a price far below the market price due to seller ignorance upon the price of such object Dissolute merchant with an attenuate belief is always take opportunity from feebleness and lacking of others by using various means, in order to earn big advantage. Such way like this in term of fiqih (study of laws pertaining of ritual obligations) is generally recognized with the title sales of najash and talaqqi ar-rukban.