Investors, including the likes of Warren Buffett, [33] and researchers have disputed the efficient-market hypothesis both empirically and theoretically. A market anomaly (or market inefficiency) is a price and/or rate of return distortion on a financial market that seems to contradict the efficient-market hypothesis. Historical Stock Market Anomalies - Long term market irregularities that contradict the efficient market hypothesis. Anomalies and Market Efficiency G. William Schwert NBER Working Paper No. 9277 October 2002 JEL No. G14, G12, G34, G32 ABSTRACT Anomalies are empirical results that. Anomalies and Market Efficiency G. William Schwert. NBER Working Paper No. 9277 Issued in October 2002 NBER Program(s): AP. Anomalies are empirical results that seem. Anomalies and Efficient Portfolio Formation on ResearchGate, the professional network for scientists. Anomalies and Market Efficiency G. William Schwert University of Rochester, Rochester, NY 14627 and National Bureau of Economic Research October 2002 Stocks sometimes thwart the efficient market theory by showing some very unusual patterns. Efficient Markets and Anomalies Chapter Summary. The efficient market hypothesis maintains that the market adjusts very rapidly to the supply of new information, and. Research Foundation of AIMR Monograph • 73 aimrpubs.org RESEARCH FOUNDATION OF AIMR MONOGRAPH Anomalies and Efficient Portfolio Formation S.P. Kothari and Jay Shanken.