The private securities fraud action under Section 10(b) of the Exchange Act and Rule 10b-5 is the most procedurally distinctive civil claim in American law, and this UpLaw guide maps it end to end. It walks the six elements the Supreme Court has assembled around a cause of action Congress never wrote — material misrepresentation or omission, scienter, connection with a purchase or sale, reliance, economic loss, and loss causation — and explains why each one carries a doctrinal trapdoor. It traces the fraud-on-the-market presumption from Basic Inc. v. Levinson through Halliburton II and Goldman Sachs, showing how price impact became the real battleground of class certification, and it unpacks the Private Securities Litigation Reform Act's particularity requirements, the Tellabs strong-inference standard, the automatic discovery stay, and the lead-plaintiff auction that decides who runs the case. It then covers the statutory safe harbor for forward-looking statements, scheme liability after Lorenzo, the narrow path to secondary-actor liability after Janus and Stoneridge, and the strict-liability alternative of Securities Act Sections 11 and 12(a)(2). A running hypothetical — the revenue restatement at Cobalt Grid Inc. — carries the doctrine from the first short-seller report through class certification, damages modeling, and settlement. Read it alongside UpLaw's companion treatments of SEC enforcement, Rule 23 class practice, and public-company disclosure.