Under the law of some community property states, married persons may agree to convert some or all of their separate property to community property. Such an agreement may be referred to as an agreement to convert separate property to community property or as a transmutation agreement.

The legal character or nature of debts of married persons may also be changed by transmutation in some community property states—changing debts of the parties’ separate estates to debts of the community estate, or debts of the community estate to debts of the separate estates. But an agreement between married persons to change a community debt to the debt of one of the spouses separate estates may not be binding on the creditor—unless the creditor agrees in writing to only look to one spouse for satisfaction of the debt.

In community property states, the laws regarding the availability and scope of transmutation agreements vary from state to state. These laws are usually located in a state’s statutes—often in the family code or domestic relations code.

Illinois is not a community property state; it is an equitable distribution state. This means that during a divorce, marital property is not automatically split 50/50 but is divided in a manner that is equitable, which may not necessarily be equal. In community property states, property acquired during the marriage is considered owned jointly by both spouses and is divided equally upon divorce. However, since Illinois does not follow community property laws, there is no legal framework for converting separate property to community property within the state. Instead, property is categorized as either marital or separate based on factors such as when and how the property was acquired. Debts are similarly divided equitably in Illinois, and any agreement to change the nature of debts between spouses would not be under the purview of community property laws but would be subject to contract law and the agreement of creditors.