Q: Can I sell on credit to a friend, whom I know and trust, without my partner’s consent?
A: You are not allowed to take risks that are not the common practice or have not been agreed upon initially without your partner’s consent. Selling merchandise on credit, or sending merchandise by regular mail, is a form of potential risk (C.M. 176:10).
Even if some people sell on credit, it is not considered common practice unless this merchandise is regularly sold on credit. Some indicate that it suffices that most sell on credit; others require that almost everyone does (see Sma 176:33; Nesivos 176:21; Aruch Hashuchan 176:30; Ohr Same’ach, Hil. Shutfin 5:2).
Nonetheless, you can sell on credit to someone who is granted credit by those who know him, even if those who do not know him do not grant him credit (Mishmeret Shalom 176:18). However, if others who know him do not grant credit, you would not be allowed to.