Trade secret disputes rarely start with something dramatic like a spy movie theft. More often, they begin with an employee departure, a vendor relationship gone sideways, a product launch, or a company discovering that a competitor suddenly knows something it spent years developing.
Under the federal Defend Trade Secrets Act, a trade secret can include many forms of financial, business, scientific, technical, economic, or engineering information, so long as the owner took reasonable steps to keep it secret and the information derives independent economic value from not being generally known. That definition is intentionally broad, which is one reason trade secret fights can involve far more than formulas and source code. Cornell’s Legal Information Institute and the World Intellectual Property Organization both describe trade secrets in expansive terms that cover technical and commercial information alike.
In this post, you’ll learn about nine categories of business information that commonly sit at the center of trade secret litigation, why those categories create conflict, and where companies often run into trouble when trying to prove secrecy. If you want a broader foundation first, it may help to start with this overview of what businesses are really trying to protect when they talk about trade secrets.
<aside> 💡 Scroll to the bottom for every post in this series.
</aside>
Trade secret law protects information, not just documents. That distinction matters. A confidential pricing model can exist in a spreadsheet, an email thread, a slide deck, or an employee’s memory. A manufacturing process may be reflected in equipment settings, manuals, supplier instructions, and training practices. A customer strategy can live inside CRM exports, call notes, and account plans.
That breadth is built into the statute. The federal definition covers information whether it is stored physically, electronically, graphically, photographically, or in writing, and whether it is tangible or intangible. Cornell LII’s text of 18 U.S.C. § 1839 captures just how wide that net can be. The Uniform Law Commission likewise identifies the Uniform Trade Secrets Act as a major framework used to protect business secrets across states.
At the same time, not every confidential document qualifies. Courts often focus on a few recurring questions:
Those issues explain why many trade secret cases become evidence-heavy fights over emails, access logs, policies, exit interviews, and contract language rather than abstract arguments about “ownership.”
Customer lists are one of the most common flashpoints in trade secret cases, but they are also one of the most misunderstood.
A simple list of companies in an industry may be easy to compile from public sources and may not look very secret. But a curated customer database can become much more sensitive when it includes nonpublic buying preferences, contract timing, pricing history, renewal risks, internal decision-makers, service issues, margin data, and relationship strategy. The WIPO guide on trade secrets notes that trade secrets often exist across records such as emails, reports, business plans, contracts, and client lists, and its more detailed guide gives customer lists as an example of information often treated as secret when compiled through ingenuity rather than simple public collection.
These disputes often arise when a salesperson leaves for a competitor and begins contacting accounts right away. The core legal question is rarely “Did the employee know customers?” It is more often whether the employee took or used nonpublic customer intelligence that gave a competitive advantage.
That is why companies often fight over: