Shulchan Aruch Chapter 245:
A Jew and a Gentile Who are Partners, How Can it Be Arranged on Shabbat (6 Paragraphs)
Note:   REMA in brackets [ ]

1. Consider if a Jew and a Gentile are partners in owning a field, oven, bath house, "a millstone of water", or partners in owning a store of merchandise.  If they stipulated from the inception of their partnership that the proceeds of the Shabbat go to the Gentile alone whether it be a little or great and a corresponding days' proceeds go to the Jew alone then it is permitted.  If they did not make this arrangement at the very beginning, then when they go to divide the proceeds the Gentile takes all of the proceeds of all of the Sabbaths and the remainder they divide evenly.  If the amount made on the Sabbath is not known then the Gentile takes one seventh for himself and the rest they divide. [There are those who permit the proceeds according to the letter of the law ( בדיעבד ) even if they did not make a stipulation and they can simply divide them.  There are those who say that the above only applies where everyone only works separately on his day.  But when they work together during the week and the Gentile works himself on the Sabbath  it is permitted to divide all the proceeds since the Gentile is working for himself and the Jew does not benefit from his work on the Sabbath because his work does depend on him to do [1].  Nevertheless, he should not take the Shabbat proceeds directly but rather divide the earnings after combining it with the other days of the week.]

2.  In the case where they made an arrangement at the beginning, if afterwards at the time of the division the Gentile wishes to divide the proceeds equally then it is permitted.

3.  Where they did not make the stipulation at the beginning, there is a way to fix it.  They can return to the seller the value of the land or they can sell it to another person, then return it and make a new act of ownership ( קנין ) together and make the correct stipulation.  If they were partners in a store and did not make the arrangement then every partner should take back their investment, abolish the partnership and then reform the partnership with the proper arrangement.  If they accepted to do work on a piece of land in a partnership then they should abolish the partnership, pardon one another of responsibilities and afterwards reform the partnership with the correct stipulation.  [If one wishes to rent his portion to another Gentile on the Sabbath or lease it then it is allowed.  This is similar to what is explained earlier in ch 244 with regard to levies and (collected) money where we explain that such practices are allowed so surely the same applies to this case where he has a Gentile partner.]

4.  A Jew may give a Gentile money to make use of even though the Gentile carries it and spends it on the Sabbath.  He may divide all the proceeds equally since the work does not depend on the Jew to be done in that bystanders would say that this Gentile is the Jew's messenger.  Also, it is not recognizable who founded the labor.  [This is only in a case where the Gentile carries and spends the money alone.   But if each person works during his day and the Jew has to work in order to make up what the Gentile does on the Shabbath then it is forbidden.  If the Jew had a collateral from the Gentile, look in 325:2]

5.  It is permitted for a Jew to give a commission to a Gentile to sell items or property as long has he does not instruct the Gentile to sell it on Shabbat. Consider the case where a Jew sold an oven to a Gentile on collateral under the arrangement that with the proceeds collected in using the oven he will pay the Jew back the value of the oven plus interest.  It is permitted for the Gentile to use such an oven on the Sabbath since it is in the property of the Gentile and the Jew does not have a share in it.  The Jew did not tell the Gentile to use it on the Shabbath so the labor the Gentile performs is on his own in order to fulfill the arrangement.

6.  If a Gentile baked in a Jewish oven on Shabbat by force and then gave the Jew the bread he baked in order to pay for the use of the oven, it is forbidden to benefit from this bread.
___________________
[1]  Translated literally. 

Translated by Jay Dinovitser DO    10/2011
ShulchanArach.com
Free for Personal Use Only