Q: A boy entrusted his card collection to a friend. If one of them is not yet bar mitzvah, is there liability of guardianship?

A: A minor under the age of bar mitzvah is not considered of legal mind (bar da’as) to be liable for guardianship. A person who entrusts an item to his care is aveidah mida’as, a willing loss (see C.M. 291:21; 188:2).

Therefore, if the cards were entrusted to a minor child, he is not liable for them, even if lost through negligence (p’shiah). Even when the boy grows older, he has no moral obligation to pay, unlike a child who damages (Pischei Choshen, Pikadon 1:17). [Parents should consider, nonetheless, their broad chinuch goal to train financial responsibility.]

When a minor entrusted his cards to a friend who is already bar mitzvah, the Shulchan Aruch rules that the guardian carries full responsibility towards the minor, including the Torah-imposed oath. The Rema, however, rules that the Torah oath does not apply to property entrusted by a minor (302:2; 96:1).

Some maintain that even according to the Rema there is a rabbinic responsibility of guardianship towards the minor (GR”A 96:8, but see P.C., Pikadon 1:[35] citing Imrei Yosher). The Shach (96:2) maintains that the guardian is liable, even according to the Rema, if he was negligent with the minor’s property.