You may see this phrase in a cease-and-desist letter, a lawsuit, an employment agreement, or a warning from a former business partner claiming you "used confidential information" that did not belong to you. It means someone is accused of taking, disclosing, or using a company's secret business information without permission, usually through theft, copying, spying, breach of a nondisclosure agreement, or other improper means. A trade secret can be a formula, customer list, manufacturing method, software process, pricing strategy, or other information that has real economic value because it is not publicly known and the owner took reasonable steps to keep it secret.

The danger is that businesses sometimes stretch this accusation far beyond what the law allows. Not every skill, idea, or memory from a prior job is a trade secret. General experience and publicly available information usually are not protected that way. A weak claim can still be used to intimidate a worker, competitor, or contractor into backing down.

These cases can lead to injunctions, money damages, and seizure orders. At the federal level, the Defend Trade Secrets Act of 2016 allows civil lawsuits in federal court; most states also follow versions of the Uniform Trade Secrets Act. If a personal injury claim involves a defective product, unsafe process, or internal company documents, trade secret objections may be used to block evidence. Courts can protect genuine secrets, but they do not get a free pass to hide misconduct.