Tortious interference under Michigan law requires proof not only that the conduct was intentional but that it was improper. What Is Tortious Interference With a Contract?Tortious interference of business – When false claims and accusations are made against a business or an individual's reputation in order to drive business away. Tortious interference occurs when someone knowingly disrupts a contract or business relationship, causing harm. We have also identified actions as improper which are not. What Is Tortious Interference With a Business Relationship? The business owner should be able to prevail over the competitor's tortious interference claim based on the First Amendment as truth is a complete defense. The interference is improper if it is illegal, independently tortious, or violates established standard of trade or profession. Tortious interference can be any unlawful tampering with a business relationship, but it is easier to prove when an actual contract exists. A valid and enforceable contract between you and another party is required to recoup for tortious interfering with a contract.