A competitor tells your largest customer that your parts fail inspection. A former vendor posts that your product is unsafe. Or the attack is aimed elsewhere, and someone says your owner pays bribes. Each statement can cost you the same account. Illinois law does not treat them the same way, and picking the wrong theory can lose a case that should have had some life in it.
The dividing line is this: a false statement about the quality of what you sell points toward commercial disparagement and the Illinois Uniform Deceptive Trade Practices Act, and a false statement about the integrity or character of the company or its people points toward defamation. Some statements do both. Most lawyers and business owners reach for the word defamation first, and that habit can be a mistake.
Chicago Business Litigation Lawyer Blog

