“Knowledge” In Tortious Interference With Contract Cases

Tortious interference with contract is an intentional tort. The knowledge element is where many claims collapse because a defendant cannot intend to induce the breach of an agreement it never knew existed. Mastering how to plead and prove knowledge—and how to attack it on defense—often decides the case before it starts. This tutorial walks through the standard, the jurisdictional variations, and the evidentiary playbook.

Ye Olde Standard

Every American formulation traces back to Lumley v. Gye, 2 El. & Bl. 216, 118 Eng. Rep. 749 (Q.B. 1853), which has been “codified” in the Restatement (Second) of Torts § 766. Comment i requires that the actor have (1) knowledge of the contract and (2) understand that its conduct is interfering with the contract’s performance.

Knowledge and intent are analytically distinct but they travel together.

Actual vs. Constructive Knowledge

Jurisdictions are split as to whether the plaintiff must show actual knowledge or whether constructive (inferable) knowledge.

The majority position accepts either. A plaintiff need not prove the defendant knew of the specific contract or its precise terms; it is enough that the defendant knew facts from which the contract’s existence can reasonably be inferred. The Nevada Supreme Court framed it this way in J.J. Industries, LLC v. Bennett, 119 Nev. 269, 275–76, 71 P.3d 1264 (2003): a plaintiff must show the defendant knew of the existing contract or, at minimum, establish facts from which the contract’s existence can reasonably be inferred.

Some jurisdictions demand more. New York generally requires the defendant’s actual knowledge of the contract. See Kronos, Inc. v. AVX Corp., 81 N.Y.2d 90 (1993). Texas likewise leans toward actual knowledge, at least in the prospective-relations variant. See Tex. Oil Co. v. Tenneco Inc., 917 S.W.2d 826, 834 (Tex. App.—Houston [14th Dist.] 1994), rev’d on other grounds.

Don’t confuse the contract tort with tortious interference with prospective economic advantage where most courts apply a “knew or should have known” standard as to the expectancy. This is a much lower bar than the contract tort’s requirement that the defendant know an actual agreement exists. California illustrates the contrast: interference with an existing contract requires knowledge of the contract (Pacific Gas & Elec. Co. v. Bear Stearns & Co., 50 Cal.3d 1118 (1990); CACI No. 2201), while the prospective-advantage tort asks whether the defendant knew or should have known of the relationship.

You Do Not Need To Prove

Every Specific Term. The defendant need not know the contract’s price, duration, or clauses—only that a binding relationship exists.
Mistake of law is no defense. A defendant who wrongly believed the agreement was unenforceable, or already terminated, is still liable if a valid contract in fact existed. Knowledge of the facts, not a correct legal conclusion, is what the tort requires.
Formal notice is unnecessary. Knowledge can be established entirely by circumstantial evidence.

Evidentiary Playbook

These cases are usually built on logic and inferences. This type of evidence often comes from:

Documents. Emails, texts, and internal memos referencing the plaintiff’s deal, the counterparty, or “the exclusivity problem” are gold. Preserve them early through a litigation hold and targeted discovery.
Prior dealings and industry custom. In a tight market, a defendant’s familiarity with standard exclusive-supply or non-compete arrangements supports an inference of knowledge.
Notice. Cease-and-desist letters, term-sheet disclosures, or a counterparty’s own statement that it told the defendant about the contract.
Timing and conduct. A defendant that approaches the counterparty immediately after the deal closes, or structures its offer to relieve the counterparty of its “commitment,” reveals knowledge through behavior.
The counterparty’s testimony. Often the single most persuasive proof: the breaching party confirming it told the defendant, “I’m already under contract.”

Plead knowledge with supporting facts. Conclusory allegations are usually worthless.

Anticipate The Usual Defenses

Expect arguments that it (a) had no actual or constructive knowledge; (b) reasonably believed the relationship was non-binding or had already ended; or (c) knew only of a general business relationship, not a contract.

Build the best possible record to foreclose each defense. Grab every fact that shows what the defendant knew and when before the defense can manufacture ambiguity.

So What?

There is no substitute for a disciplined, document-driven approach to this element. Assume the “constructive knowledge” standard is not available to build the greatest record possible so the complaint reads more like an indictment.

David Seidman is the principal and founder of Seidman Law Group, LLC. He serves as outside general counsel for companies, which requires him to consider a diverse range of corporate, dispute resolution and avoidance, contract drafting and negotiation, real estate, and other issues. He can be reached at david@seidmanlawgroup.com or 312-399-7390.