By the Bais Hora'ah
We received two questions dealing with similar issues of partners requesting compensation for an investment in a shared endeavor.
One of two partners in a service business invested company funds into developing a website. The site took off, and the company revenue skyrocketed. Now the partner is demanding compensation for the time he invested into developing the website. Is he entitled to payment?
Two partners opened a store, making a joint commitment to be in their store from nine to five each day. In recent weeks, one of the partners has consistently arrived late, leaving the other partner to manage the store himself, with great difficulty. Is he entitled to payment for doing double work during the hours he managed the store on his own?
According to halachah, a partner who cultivates a jointly owned field without discussing it with his partner is considered akin to a sharecropper who received permission to cultivate a field (yoreid b’reshus). Not only is he reimbursed for all personal funds invested into the property, he is also entitled to the standard local hourly wages for a laborer who cultivates fields for the time he put into cultivating his partner’s portion of the field, which is more than the typical wage paid to day laborers (Shulchan Aruch Choshen Mishpat 178:3). This is true even if he planted trees in a field ordinarily used for wheat, since he has equal say in deciding how to use the field.
The She’eilas Yaavetz (6) deduces from this halachah that a partner who does even minimal work to improve a jointly held enterprise is entitled to payment for his work. [If a field is family owned, and one brother invested time and energy into improving it, the Rishonim debate whether he is entitled to payment. We rule that he is reimbursed for heavy labor invested into the field, but if he did light, administrative-style work, such as hiring workers to work in the field, we assume that, as a brother, he is willing to overlook the minimal amount due for such work to one another. Partners, on the other hand, are assumed to expect payment even for light work (ibid. 287:1).]
In theory, then, it would seem that the partners in both of the above cases should be entitled to payment.
Nevertheless, some poskim differentiate between the two cases.
In the first case, since neither partner was required, as part of the partnership agreement, to develop a website, the one who did so of his own initiative is entitled to payment for his work. His counterpart cannot claim that had he known his partner was working on a website, he would have invested time as well instead of paying his partner to do it. Since building the website was not discussed as part of their partnership agreement, his partner had no right to demand any of his time on that project, and the partner is therefore entitled to payment for the time he volunteered.
The case of the partner who was chronically late to the store is different, however. Since punctual arrival was part of the original agreement, the latecomer can claim that had his partner told him that he was overexerting himself and that he needed him to come on time, he would have complied, and since his partner didn’t say anything, he assumed that he was willing to forgo payment for handling the store alone.
This is only true, however, if the latecomer was tardy out of negligence. If it was impossible for him to be in the store one time – if he was ill, for instance, or if he moved to a different neighborhood and could not possibly arrive at nine in the morning – then his partner can demand payment for the time. He can claim, legitimately, that there was no point in informing his partner that he wanted him there on time since that it was impossible for him to comply (Nesivos 177:4 and 287:2; Erech Shai 176; Shu”t Maharsham 4:96. Minchas Pittim  rules, however, that partners never forgo payment for such work).
If a partner did tell his tardy counterpart to start coming on time because it was hard for him to run the store on his own, he is probably entitled to payment if his partner failed to comply (Pischei Choshen, Sechirus 8, fn. 73). Obviously, the punctual partner is entitled to clearly stipulate for the future that he be paid for managing the store on his own (see She’eilas Yaavetz 6).
As with all partnerships, if certain stipulations were made in the original partnership agreement, or if there are local customs governing such partnerships (minhag hamedinah), they would supersede what we have discussed above.