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Power And Statistical Significance In Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach Feb 2020

Power And Statistical Significance In Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach

Faculty Scholarship at Penn Law

Event studies, a half-century-old approach to measuring the effect of events on stock prices, are now ubiquitous in securities fraud litigation. In determining whether the event study demonstrates a price effect, expert witnesses typically base their conclusion on whether the results are statistically significant at the 95% confidence level, a threshold that is drawn from the academic literature. As a positive matter, this represents a disconnect with legal standards of proof. As a normative matter, it may reduce enforcement of fraud claims because litigation event studies typically involve quite low statistical power even for large-scale frauds.

This paper, written for ...


The Logic And Limits Of Event Studies In Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach, Jonathan Klick Jan 2018

The Logic And Limits Of Event Studies In Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach, Jonathan Klick

Faculty Scholarship at Penn Law

Event studies have become increasingly important in securities fraud litigation after the Supreme Court’s decision in Halliburton II. Litigants have used event study methodology, which empirically analyzes the relationship between the disclosure of corporate information and the issuer’s stock price, to provide evidence in the evaluation of key elements of federal securities fraud, including materiality, reliance, causation, and damages. As the use of event studies grows and they increasingly serve a gatekeeping function in determining whether litigation will proceed beyond a preliminary stage, it will be critical for courts to use them correctly.

This Article explores an array ...


“Fine Distinctions” In The Contemporary Law Of Insider Trading, Donald C. Langevoort Jan 2013

“Fine Distinctions” In The Contemporary Law Of Insider Trading, Donald C. Langevoort

Georgetown Law Faculty Publications and Other Works

William Cary’s opinion for the SEC in In re Cady, Roberts & Co. built the foundation on which the modern law of insider trading rests. This paper—a contribution to Columbia Law School’s recent celebration of Cary’s Cady Roberts opinion, explores some of these—particularly the emergence of a doctrine of “reckless” insider trading. Historically, the crucial question is this: how or why did the insider trading prohibition survive the retrenchment that happened to so many other elements of Rule 10b-5? It argues that the Supreme Court embraced the continuing existence of the “abstain or disclose” rule, and ...


Insider Trading And The Gradual Demise Of Fiduciary Principles, Donna M. Nagy Jan 2009

Insider Trading And The Gradual Demise Of Fiduciary Principles, Donna M. Nagy

Articles by Maurer Faculty

Recent SEC enforcement actions, such as the case filed against Dallas Mavericks' owner Mark Cuban, raise the question whether deception by a fiduciary is essential to the Rule 10b-5 insider trading offense. Under the Supreme Court's classical and misappropriation theories, the answer is clearly yes - each theory has a fiduciary principle at its core. Yet lower courts and the SEC frequently disregard the Court's explicit dictates, and a consensus is emerging that insider trading rests simply on the wrongful use of material nonpublic information, regardless of whether a fiduciary-like duty is breached. Although this view of insider trading ...


Contracting Access To The Courts: Myth Or Reality? Bane Or Boon?, Jeffrey W. Stempel Jan 1998

Contracting Access To The Courts: Myth Or Reality? Bane Or Boon?, Jeffrey W. Stempel

Scholarly Works

Many scholars of the dispute resolution system perceive a sea change in attitudes toward adjudication that took place in the mid-1970s. Among the events of the time included the Pound Conference, which put the Chief Justice of the United States and the national judicial establishment on record in favor of at least some refinement, if not restriction, on access to courts. In addition, Chief Justice Burger, the driving force behind the Pound Conference, also used his bully pulpit as Chief Justice of the Supreme Court to promote ADR, particularly court-annexed arbitration. The availability of judicial adjuncts such as court-annexed arbitration ...