Where one party breaches a contract because a third party induced them to, tortious interference reaches the third party. The usual elements are a valid contract or business expectancy, the defendant’s knowledge of it, intentional and improper interference causing a breach or termination, and resulting damage.
Improper is the contested element. Competition is lawful, and persuading someone to take a better deal is ordinarily what markets are for. Interference generally becomes actionable when the means are wrongful — misrepresentation, threats, inducing a breach of a known non-compete, or misuse of confidential information.
Two variants matter. Interference with an existing contract is easier to establish. Interference with a prospective business relationship requires showing a reasonable expectancy rather than a signed agreement, and courts are more cautious about it.
The practical attraction is that the third party is often better funded than the breaching party, and the claim can carry different damages — and in some circumstances punitive exposure — than a contract claim against the party who actually breached.