In Behar, one of this week’s parshiyos, the Torah commands us in regard to some of the laws of buying and selling. The pasuk says, “Vechi simkiru mimkar la’amisecha … al tonu ish es achiv – When you make a sale to your fellow … do not afflict one another.” The Gemara in Baba Metzia 51a derives from this pasuk that one may not overcharge when selling an item without informing the buyer. This is referred to as ona’ah. The Gemara says that if one charges more than a sixth more than the market value of an item, the sale is void. If one charges less than a sixth more, the sale is valid. If one charges exactly a sixth more, the sale is valid; however, the seller must return the overcharge.
The Rush, in the fourth perek of Baba Metzia, says that he is not sure whether one is prohibited from intentionally charging less than a sixth more than the market value. Even though the sale is valid and the seller does not have to return the overcharge, perhaps it is prohibited – for this too is considered ona’ah. The reason that the sale is valid and the seller may keep the overcharge is because we assume that the buyer will be mochel (forgo) on a small percentage. The Smah (Choshen Mishpat 227:14) says that one may not claim that he was not willing to forgo the overcharge of less than a sixth. Or, says the Rush, perhaps it is part of the normal process of transactions to charge a little more – and it is not considered ona’ah.
The Ramban, in his commentary on the Torah, says that even though the Gemara in Baba Metzia 56b derives from a pasuk that ona’ah does not apply to land, the prohibition nevertheless applies. The exclusion is only on the monetary aspect, but if one charges more than a sixth for the sale of land he will have transgressed the lav. The reason that one does not have to return the ona’ah of a real estate purchase, even if it is more than a sixth extra, is because we assume that people will forgo the extra amount – just as they would when it is less than a sixth on the sale of an item. However, in both circumstances, it is forbidden to do so.
The Sefer Hachinuch (mitzvah 337) takes a different view on this matter. He says that one is completely permitted to charge up to a sixth more than the market value of movable objects. He agrees with the Ramban that even though one does not have to return the extra amount that he charged for real estate, even if it exceeds a sixth, it is nonetheless forbidden to do so.
The Minchas Chinuch says that the Rambam agrees with the Sefer Hachinuch (that one is permitted to charge up to a sixth more for movable objects). He proves the Rambam’s view that it is permitted because the Rambam says that one does not receive lashes when he transgresses this prohibition. This is because it is nitein letashlumin (one must repay) i.e. he must return the overcharge. Since the halacha is that one is not required to return an overcharge of up to a sixth, he should receive lashes in that case since it is not returnable.
We find this concept by the prohibition of hitting another. If the wound is significant enough to require damages amounting to more than a prutah, the damager does not receive lashes since he must pay money. However, if the wound does not amount to damages worth a prutah he receives lashes since he cannot repay. Therefore, if it would be prohibited to charge up to a sixth more, the seller should receive lashes since he is not required to repay.
The Minchas Chinuch, however, says that this is not necessarily proof that the Rambam’s view is that one is permitted to charge up to a sixth more than the value of movable objects. This is so because, as mentioned earlier, the reason that one is not required to return the ona’ah of up to a sixth is because the buyer is mochel the extra amount. Hence, from a technical standpoint, one is required to return the extra amount – except that in this case he was mochel the obligation.