Some creditors—such as home mortgage lenders and automobile lenders—require the borrower/debtor to secure or collateralize the loan with the property being purchased. If the debtor defaults and fails to timely make the payments on the loan, this type of secured loan agreement allows the lender to foreclose on or seize the property (real estate or automobile) and sell it to repay the loan. In other words, in the loan agreement, the debtor voluntarily gives the creditor a lien on the property (a voluntary lien).

But many creditors are unsecured creditors—meaning their agreement with the debtor does not expressly provide for a lien on any property to secure payment of the debt. These creditors must generally file a lawsuit and secure a judgment against the debtor—or follow other processes prescribed by law—in order to place a lien on any of the debtor’s property, such that the creditor can force the sale of the property to satisfy the lien. Such a lien is broadly known as an involuntary lien.

Credit card companies, utility companies, cellular phone service providers, and hospitals who provide medical services are examples of unsecured creditors whose extensions of credit are not secured by a voluntary lien, but who may be able to secure an involuntary lien.

Similarly, governmental entities—such as counties that assess property taxes and the Internal Revenue Service (IRS) that collects federal income taxes—may place involuntary liens on property to satisfy tax obligations.

Contractors who provide labor or materials to improve real estate (home construction or remodeling)—and auto mechanics who service and repair automobiles—may file an involuntary mechanic’s and materialman’s lien to secure payment for the materials and labor.

And in some states, a parent, current or former spouse, or the state may place involuntary liens on property to secure payment of child support obligations or marital property obligations.

In Maine, secured creditors, such as mortgage lenders and auto loan providers, have the right to foreclose or repossess the property if the debtor defaults on the loan, as these loans are secured by the property itself through a voluntary lien. Unsecured creditors, on the other hand, do not have such security interests and must pursue legal action to obtain a judgment against the debtor to place an involuntary lien on the debtor's property. This process allows them to potentially force the sale of the property to satisfy the debt. Credit card issuers, utility companies, and medical service providers are examples of unsecured creditors who may seek involuntary liens after obtaining a court judgment. Government entities can also impose involuntary liens for unpaid taxes, such as property taxes or federal income taxes. Additionally, contractors and auto mechanics can file mechanic's and materialman's liens for unpaid labor or materials provided. In Maine, involuntary liens can also be used to secure payment of child support or marital property obligations, ensuring that individuals fulfill their legal financial responsibilities.