To: Moominoid who wrote (52909 ) 6/28/2006 6:40:33 PM From: shades Read Replies (2) | Respond to of 116555 There are lots of well know inefficiencies in the market that still persist. The Sell in May and Go Away phenomenon is one, that everyone knows about but it is still there. Why? econpapers.repec.org Stock Market Efficiency Withstands another Challenge: Solving the “Sell in May/Buy after Halloween” Puzzle Edwin D Maberly (edwin.maberly@canterbury.ac.nz) and Raylene M Pierce (piercer@lincoln.ac.nz) Additional contact information Edwin D Maberly: University of Canterbury Econ Journal Watch, 2004, vol. 1, issue 1, pages 29-46 Abstract: Examining the years 1970 to 1998, Bouman and Jacobsen (2002) document unusually high monthly returns during the November-April periods for both United States (U.S.) and foreign stock markets and label this phenomenon the Halloween effect. Their research suggests that the Halloween effect represents an exploitable anomaly and has negative implications for claims of stock market efficiency. Re-examining Bouman and Jacobsen’s empirical results for the U.S. reveals that their results are driven by two outliers, the “Crash” of October 1987 and the collapse of the hedge fund Long-Term Capital Management in August 1998. After inserting a dummy variable to account for the impact of the two identified outliers, the Halloween effect becomes statistically insignificant. This anomaly is not economically exploitable for U.S. equity markets. We extend the research to the S&P 500 futures contract and find no evidence of an exploitable Halloween effect over the period April 1982-April 2003. Keywords: efficient markets; trading rules; outliers; anomalies (search for similar items in EconPapers) JEL-codes: G14 G11 (search for similar items in EconPapers) View list of references Downloads: (external link)econjourn ... t%20April%202004.pdf (application/pdf) Related works: This item may be available elsewhere in EconPapers: Search for items with the same title. Access Statistics for this article Econ Journal Watch is edited by Daniel Klein And like that there are other inefficiencies to exploit. I don't really have an answer about why they haven't all been exploited to death. They just haven't. Maybe one day hedge funds will have enough capital and smarts to do it. But apparently they don't yet. Or the existence of an inefficiency of this sort causes traders to pile on and accentuate it? I don't believe for one second that retail folks will ever be able to exploit anything the way industry insiders do - they have better information and they have crooked crony friends in government.Some people thought that the World was flat when it is so obviously round... Hehe - A read on wiki contradicts that recent false memory - People always want to think they are smarter than the next guy or the old guy - but that isn't always the case:en.wikipedia.org It is commonly assumed that people from early antiquity generally believed the world was flat, but by the time of Pliny the Elder (1st century) its spherical shape was generally acknowledged. At that time Ptolemy derived his maps from a curved globe and developed the system of latitude and longitude (see clime). His writings remained the basis of European astronomy throughout the Middle Ages. The common misconception that people before the age of exploration believed that Earth was flat entered the popular imagination after Washington Irving's publication of The Life and Voyages of Christopher Columbus in 1828. In the United States, this belief persists in the popular imagination, and is even repeated in some widely read textbooks. Thomas Bailey's The American Pageant states that "The superstitious sailors ... grew increasingly mutinous...because they were fearful of sailing over the edge of the world"; however, no such historical account is known.[1] Actually, sailors were probably among the first to know of the curvature of Earth from daily observations — seeing how shore landscape features (or masts of other ships) gradually descend/ascend near the horizon. A few early Christian writers questioned or even opposed the sphericity of the Earth on theological grounds, but these writers are not thought to have been influential in the Middle Ages due to a scarcity of references to their work in medieval writings. The dominant textbooks of the Early Middle Ages supported the sphericity of the Earth. Even before the translation of the works of Aristotle and Ptolemy in the 1100s, the geocentric model had supplanted any doubts about the Earth's sphericity in the minds of the learned people of Europe. This did not settle, however, the question of whether the antipodes were habitable, or even reachable. Despite the wide availability of scientific knowledge at present, there are still some who believe that Earth is flat. Until recently there was a Flat Earth Society in the USA, some members of which regarded spherical satellite images of the Earth as aberrations.