Q: I purchased something for the partnership, but it was stolen from my car. Am I solely liable for the theft?
A: Partners are generally considered shomrei sachar (paid guardians) on the joint property, and are therefore liable for theft. However, if the partnership agreement did not include guarding the joint property, some maintain that they are considered only shomrei chinam (unpaid guardians), and they are not liable for theft (see Rema 176:8; Shach 176:16; Machaneh Ephraim, Hil. Shomrim #36).
Furthermore, if the partners operate the business and work on behalf of each other, the exemption of be’alav imo (the owner was in his service) would usually apply. On the other hand, if they are investment partners and others operate the business, be’alav imo would not apply (C.M. 176:8; Pischei Choshen, Shutfim 1:29-31).
If partners worked on a client’s item, and one took it to return to the owner and lost it, he alone is responsible. The exemption of be’alav imo does not apply, since the item is not theirs (Mishpat Shalom 176:8, citing Pe’er Hador).