In accordance with Article 43 of the Family and Guardianship Code, the shares of the spouses in the joint property are equal. This rule leads to the assumption that each of the spouses, regardless of the contribution to the joint property, has a share in it of ½. This means that even if one of the spouses had a significantly higher income than the other, it will not be significant, because the regulations assume an equal share in the joint property. In this way, the legislator expressed the idea of ​​equality of spouses in property relations, also after the termination of joint property. However, there is a way to refute this presumption of equality. This provision allows for a request that the determination of shares in joint property be made taking into account the extent to which each of the spouses contributed to the creation of this property. Only the existence of valid reasons allows the request to be accepted. However, it is difficult to determine "important reasons" because the Code does not specify this concept. When determining the extent to which each of the spouses contributed to the creation of joint property, the court is required to take into account the amount of personal work involved in raising children and in the common household.

Not only a spouse may request to establish shares. This right also applies to the spouses' heirs, provided that the testator has previously brought an action for annulment of the marriage or for divorce or has applied for a separation decision.