Under California’s Securities Act (Corp. Code, 25400 and 25500, as under federal securities laws, the plaintiff must allege and prove loss causation–that is, that the alleged misstatement caused the rise or decline in stock price over which the plaintiff sues. When the suit is brought in federal court, the loss causation element, like the rest of the fraud-based claim, must be alleged with particularity under FRCP 9(b). Here, plaintiffs failed to allege loss causation adequately, so their suit was properly dismissed.