Guide · Risk Management
Insider Trading: Where the Legal Line Actually Sits
The term gets used loosely for anything that feels unfair, but the actual legal definition turns on two specific things: what you knew, and whether you had a duty not to use it.
Insider trading, in its illegal form, means trading a security based on material, non-public information while owing a duty of trust or confidence not to use that information for personal gain — "material" meaning information a reasonable investor would consider important to a decision to buy or sell, and "non-public" meaning it hasn't yet been disclosed to the broader market.
Both conditions matter, and missing either one changes the analysis entirely. A company's CEO buying shares based on knowledge of an unannounced earnings beat is the clearest case — material information, a clear duty owed to shareholders, used for personal benefit. Someone overhearing a stranger's conversation at a restaurant and trading on it occupies much murkier legal territory, since the "duty" element is far less obviously present, though regulators have successfully pursued cases built on exactly that kind of indirect information chain.
Not all trading on an informational edge is illegal — a professional analyst who builds a well-researched thesis from public filings, industry contacts, and careful observation isn't insider trading just because that analysis turns out to be more accurate than the average investor's; the line specifically concerns material information that's genuinely non-public and obtained in breach of a duty, not simply "knowing more than someone else."