Tortious interference, also known as intentional interference with contractual relations, in the common law of torts, occurs when one person intentionally damages someone else's contractual or business relationships with a third party, causing economic harm. As an example, someone could use blackmail to induce a contractor into breaking a contract; they could threaten a supplier to prevent them from supplying goods or services to another party; or they could obstruct someone's ability to honor a contract with a client by deliberately refusing to deliver necessary goods. A tort of negligent interference occurs when one party's negligence damages the contractual or business relationship between others, causing economic harm, such as, by blocking a waterway or causing a blackout that prevents the utility company from being able to uphold its existing contracts with consumers. Tortious interference with contract rights can occur when one party persuades another to breach its contract with a third party (e.g., using blackmail, threats, influence, etc.) or where someone knowingly interferes with a contractor's ability to perform his contractual obligations, preventing the client from receiving the services or goods promised (e.g., by refusing to deliver goods). The tortfeasor is the person who interferes with the contractual relationship between others. When a tortfeasor is aware of an existing contract and deliberately induces a breach by one of the contract holders, it is termed "tortious inducement of breach of contract." Tortious interference with business relationships occurs where the tortfeasor intentionally acts to prevent someone from successfully establishing or maintaining business relationships with others. This tort may occur when one party knowingly takes an action that causes a second party not to enter into a business relationship with a third party that otherwise would probably have occurred. An example is when a tortfeasor offers to sell a property to someone below market value knowing they were in the final stages of a sale with a third party pending the upcoming settlement date to formalize the sale writing.