In law, secured transactions are an integral part of the Uniform Commercial Code (UCC). Article 9 of that Code governs personal-property secured transactions in all fifty American states. The provisions of Article 9 supply a predictable way of creating and enforcing security interests in movable property, intangible property, and fixtures. Because of the importance of secured transactions, commercial lawyers typically have (or claim to have) great familiarity with the provisions of Article 9. Real-property secured transactions are governed not by Article 9 but by real-property laws that are not necessarily uniform from state to state.
Security interests are particularly valuable in bankruptcy, because those creditors who have security interests in a bankrupt debtor's estate have priority—i.e., will get paid before—creditors who lack such interests ("unsecured" creditors).