The U.S. Supreme Court's recent Dura Pharmaceuticals decision requires a plaintiff to show a market decline (ex post losses), as opposed to price inflation at the time of purchase (ex ante losses), in order to maintain an action for securities fraud. However, this paper points out that Dura has made it possible for corporate management to strategically disclose information that purposely obscures the causal connection. Indeed, it is not unusual for a company to release material good news on the same day that it provides the market with a corrective disclosure regarding concealed risk. Then it is very difficult for plaintiffs to demonstrate that the material misrepresentation caused investors an economic loss by an ex post rule. Hence, this paper argues that we should adopt the view of ex ante rule in Taiwan. That is, an artificial price inflation on the date of purchases is sufficient for plaintiff to allege loss causation.