Efficient market hypothesis and fraud on the market theory: A new perspective for class actions

Following recent judgement of the Supreme Court of US (June 2014), several commentators had declared that “Securities class actions are here to stay” (insidecounsel.com – September 2014, 11). This paper provides a critical perspective on this judgement, which “implicates substantive issues at the intersection of economic theory, financial markets, and securities regulation” (128 Harv. L. Rev. 291 2014-2015, 291), and shows that we must be much more careful. This recent judgement is based on the Fraud on the Market Doctrine, which was introduced in 1973 in order to preserve the class action procedure in securities fraud litigation. The characteristic of the Fraud on the Market Doctrine is to have been structured from one of the most popular financial theory: Efficient Market Hypothesis. In this paper, by analysing the implementation of the Efficient Market Hypothesis in Fraud on the Market Theory, we argue that if the Supreme Court had to take position for a second time about the Fraud on the Market Doctrine it is due to the practical difficulties inherited from Efficient Market Hypothesis and that have raised several problems to the US courts, including the Supreme Court. This issue is illustrated by the definition of Efficient Market Hypothesis lawyers used (“most” vs “all”/”fully”). As this paper shows, if “Securities class actions are here to stay”, the opportunity to open such a class action is strongly reduced in the facts

The diagram of the path in pursing medical treatment for the patient.

<p>The diagram of the path in pursing medical treatment for the patient.</p

<i>S. japonicum</i> egg nodes visible in the submucosa.

<p>(A) The ascending colon and (B) the sigmoid colon.</p

Numbers of advanced schistosomiasis japonica in China.

<p>(A) In each province by 2008; (B) in each province by 2003 and new cases found from 2004 to 2008; and (C) the coverage rates of the aid-project in the cases at the levels of nation or province (Anhui) over 2004 to 2008.</p

Additional file 2: of Detecting genotyping errors at Schistosoma japonicum microsatellites with pedigree information

Genotype data on offspring miracidia and their parental worms. (XLS 48 kb

Individual and pooled preventive effects (PRs) of three consecutive rounds of ACWT against schistosome in humans.

<p>PR, ratio of infection prevalence after three rounds of ACWT to prevalence before. ACWT refers to annual community-wide treatment. Diamond and vertical dashed line indicate combined PR, and horizontal lines indicate 95% confidence intervals.</p

The flow diagram of paper review process.

<p>ACWT refers to annual community-wide treatment. One article may contain one or more studies.</p

Individual and pooled preventive effects (PRs) of two consecutive rounds of ACWT against schistosome in humans.

<p>PR, ratio of infection prevalence after two rounds of ACWT to prevalence before. ACWT refers to annual community-wide treatment. Diamond and vertical dashed line indicate combined PR, and horizontal lines indicate 95% confidence intervals.</p

Individual and pooled preventive effects (PRs) of one round of ACWT against schistosome in humans.

<p>PR, ratio of infection prevalence after one round of ACWT to prevalence before. ACWT refers to annual community-wide treatment. Diamond and vertical dashed line indicate combined PR, and horizontal lines indicate 95% confidence intervals.</p

Control Efficacy of Annual Community-Wide Treatment against <i>Schistosoma japonicum</i> in China: A Meta-Analysis

<div><p>Backgrounds</p><p>Human schistosomiasis is caused by <i>schistosome</i>, with annual loss of over 70 million disability adjusted life years in the world. China is endemic with <i>Schistosoma japonicum</i> and large-scale chemotherapy with praziquantel has become the mainstay of control in China since 1990s. However, the control effects of mass treatment in the field have been uneven. Moreover, mass treatment has come into a wide use in other countries with limited health resources. Therefore, a better understanding of the control effect of mass treatment is in an urgent need.</p><p>Methods</p><p>We performed a systematic search of the literature to investigate the control efficiency of annual community-wide treatment (ACWT, treatment to an entire community without any preliminary screening) with a single dose of PZQ (40 mg kg⁻¹ bodyweight) against schistosome in humans in China. Three Chinese literature databases, including China National Knowledge Infrastructure, WanFang and Chinese Scientific Journal Databases, and the PubMed were searched. Pooled prevalence ratios (prevalence after to before treatment) were used to assess effect. Our protocol is available on PROSPERO (No. CRD42013003628).</p><p>Results</p><p>22 articles were included. Meta-analyses on data from 18 studies on one round of ACWT, 17 studies on two consecutive rounds and 6 studies on three consecutive rounds were performed. The results showed control effects of ACWT plus other measures were statistically significant, with prevalence ratios being 0.38 (0.31, 0.46) for one round, 0.28 (0.22, 0.35) for two rounds and 0.22 (0.10, 0.46) for three rounds. When ACWT was performed alone or with health education only, the values for one and two rounds were 0.389 (0.307, 0.492) and 0.348 (0.300, 0.403), respectively.</p><p>Conclusions</p><p>The control effect of ACWT alone or with other measures is significant and increases with the number of rounds. Such program is recommended in high endemic areas and the criteria yet merit further assessment.</p></div