Lien

A lien is one of the oldest devices in commercial and property law: it gives a creditor an enforceable interest in specific property belonging to a debtor, allowing the creditor to be paid out of that property if the underlying debt is not discharged. The debtor typically retains possession and even ownership, but cannot sell or refinance the asset free and clear without addressing the lien.

Liens come in several recognized forms:

• Consensual liens, created by agreement, such as a mortgage on real estate or a security interest in goods under Article 9 of the U.S. Uniform Commercial Code.
• Statutory liens, imposed by legislation, including mechanic's liens for construction work, tax liens, and maritime liens on vessels.
• Judicial liens, arising from a court judgment that attaches to a debtor's property.
• Common-law possessory liens, where a service provider (an innkeeper, repairer, or carrier) retains possession of goods until paid.

Liens generally must be perfected — typically by filing or registration — to be enforceable against third parties and to establish priority. Priority among competing liens is usually governed by the rule prior in tempore, potior in jure ("first in time, first in right"), though tax liens and certain statutory liens may jump the queue.

In international and sovereign contexts, the concept extends to maritime liens under instruments like the 1993 International Convention on Maritime Liens and Mortgages, which lets claimants arrest a ship in foreign ports. Sovereign debt restructurings also raise lien-like questions: holdout creditors in the NML Capital v. Argentina litigation (decided by U.S. courts in 2012–2014) leveraged the pari passu clause to similar effect, even without a formal lien.

For policy researchers, liens matter because they determine who bears loss in insolvency, shape access to credit, and — in cross-border settings — interact with sovereign immunity, judgment enforcement, and asset recovery regimes.