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In the area of securities class actions, David Tabak has testified on topics including class certification, liability, materiality, affected trading volume, and damage calculations in cases with allegations such as improper valuations, accounting irregularities, and merger disputes. He has also provided written and oral testimony on the valuation of equity, financial derivatives, fixed-income instruments, businesses, and litigation settlements. Dr. Tabak was commended in Who's Who Legal Arbitration Expert Witness Guide for his testifying experience as an expert witness. Publications by Dr. Tabak propounding analyses for examining market efficiency and parsing out the effects of confounding news in event studies have been cited favorably by courts including the Second Circuit and the Southern District of New York, as well as the Federal Court of Australia.


Dr. Tabak has appeared as an expert in state, federal, Delaware Chancery, and bankruptcy courts, and before arbitration panels, including the National Association of Securities Dealers (NASD), the American Arbitration Association, JAMS, the International Dispute Resolution Centre, and the International Chamber of Commerce International Court of Arbitration. His non-litigation work has included developing a risk-scoring model for a reinsurance company, assisting financial institutions in new product development, analysis of potential insider trading for a financial institution, and analyses of potential exposure for investors considering investments in or acquisitions of companies facing litigation.

Dr. Tabak has published in his areas of expertise in forums such as St. John's Law Review and Shannon Pratt's Business Valuation Update, and has published peer-reviewed articles in Litigation Economics Review and the Journal of Forensic Economics. Dr. Tabak is also the author of book chapters and has served as a member of BV Q&A Update's expert author panel and as a referee for peer-reviewed journals. His publications have covered 10b-5 damages analyses, commercial disputes, economic analysis of market efficiency, valuation discounts for lack of marketability, and the application of statistics in litigation analyses, among other topics. Dr. Tabak has been an invited speaker at the Securities and Exchange Commission and a presenter at forums that provide continuing legal education credits or continuing professional education credits for appraisers. Dr. Tabak enjoys participating in roundtable discussions at law firms where he and lawyers share ideas and debate current issues in litigation.


  • PhD and MA in economics, Harvard University
  • BS in economics and BS in physics, Massachusetts Institute of Technology