Back-Testing Magic an Analysis of the Magic Formula Strategy
Total Page:16
File Type:pdf, Size:1020Kb
Back-testing Magic An analysis of the Magic Formula strategy Master Thesis Investment Analysis Author: R.H. Blij Student number: 323008 Supervisor: Dr. R.G.P. Frehen Chairman: Dr. F. Feriozzi Department: Department of Finance Faculty: Economics and Business Administration Date: October 18, 2011 Abstract This paper performs a back-test of the magic formula strategy first introduced by Joel Greenblatt in 2006 in his book “The little book that beats the market”. The magic formula is a method of stock selection where the highest combined scores for Return on Capital and Earnings Yield qualify as the best investment. Greenblatt (2010) provides results from the magic formula strategy that are able to persistently outperform the market from 1988 to 2009. I try and mimic these returns to either validate or reject the claims as made by Greenblatt. To do so a dataset is composed of the NYSE, AMEX and NASDAQ where all stocks are ranked using Earnings Yield and Return on Capital. The results confirm the findings as stated by Greenblatt where both the value-weighted and equally-weighted abnormal returns exhibit strong persistence at high significance. The results remain persistent under alternating investing conditions, like a longer holding period and higher required market capitalization for each stock. Furthermore, a sub sample is tested from the publication of the book in 2006 to 2010. Results during this period are statistically insignificant. Either the publication of the Magic formula has led to its own demise, or the overall downturn in the market temporarily invalidated its use. No decisive conclusion can be made in this respect. Acknowledgements: I would like to thank my supervisor Dr. R.G.P. Frehen for his invaluable help and patience when writing this paper. The Chairman, Dr. F. Feriozzi, for taking the time to read this paper and his position on the exam committee. Furthermore, I would like to thank my family, friends and especially my girlfriend for sticking by me even during stressful times. 1 Table of Contents 1. Introduction ........................................................................................................................... 3 2. Literature ............................................................................................................................... 6 2.1 The Magic Formula ............................................................................................................................................. 6 2.2 Market anomaly................................................................................................................................................... 8 2.3 Performance ...................................................................................................................................................... 12 2.4 Explaining value strategy persistence ............................................................................................................... 13 3. Hypothesis ............................................................................................................................ 17 3.1 Additional hypotheses: ...................................................................................................................................... 18 4. Data & Methodology ........................................................................................................... 20 4.1 Data ................................................................................................................................................................... 20 4.2 Portfolio formation: ........................................................................................................................................... 21 4.3 Methodology ..................................................................................................................................................... 23 5. Empirical Results ................................................................................................................. 26 5.1 Magic formula portfolio .................................................................................................................................... 26 5.2 Alterations: ........................................................................................................................................................ 35 5.3 Sub-sample ........................................................................................................................................................ 39 6. Conclusion ............................................................................................................................ 40 6.1 Hypotheses ........................................................................................................................................................ 40 6.2 Conclusion......................................................................................................................................................... 43 7. Recommendations ................................................................................................................ 46 References .................................................................................................................................... 47 APPENDIX A: Inversed Magic ................................................................................................. 51 APPENDIX B: Group portfolios ............................................................................................... 57 APPENDIX C: MF complete regression statistics ................................................................... 59 APPENDIX D: Subsample Statistics ......................................................................................... 61 2 1. Introduction very investor seeks a way to outsmart Mr. Market, the next best investment strategy that E earns high abnormal returns. Achieving abnormal return is often dubbed as impossible when we believe the Efficient Market Hypothesis (EMH) to hold true. It is generally believed that security markets are extremely efficient and reflect all available information. As soon as new information arises all market participants quickly incorporate the news into their price, without delay. Thus, predicting future stock prices using past information is a futile endeavor. If all market participants have the same information, all parties would trade on this information making the best obtainable return the same as the market return. In result, the optimal portfolio is one that is completely invested in the Market. The investor is unable to earn above-average returns without accepting above-average risks1. This paper discusses the question whether or not it is possible to obtain an abnormal return by looking at publically traded information used in The Magic Formula strategy. Clearly this would violate the EMH and would thus be a market anomaly. Forgoing literature has identified several anomalies, for example persistent higher returns in January and seasonal effects in stock prices. Keim (1998) provides an extensive overview of these different anomalies. One anomaly that has increased its presence in current literature is the persistent outperformance of value investing strategies. Value investing is school of thought on investing were the company‟s fundamental values are pertinent in the decision process to either buy or sell the share. This approach was first advocated by Benjamin Graham and David Dodd in 1928 at the Columbia Business School. The idea behind the approach is simple: “invest in stocks that have low price relative to some measure of their fundamental value”. In this context the fundamental value can be book value, market value, intrinsic value etcetera. Even though the idea is simple, there has been a lot of criticism that if the price is low, the possibility that it will drop further is still very likely. Graham himself has several value measures he considers to make sure that besides being cheap the company is still healthy and thus has potential. Graham looks for stocks trading at a discount to their Net Current Asset Value (NCAV). In essence stocks which have a market value lower than their current asset value. In the event of a bankruptcy the investor can still recover his initial investment as the stock is trading 1 For more information see; Malkiel (2003) 3 below its‟ liquidation value. This strategy utilizes the book-to-market anomaly, which is well reported by Fama and French (1992) as a key variable in explaining stock market variance. Value investing differs from regular investment theory in that it does not believe that the CAPM and beta are good determinants for a share‟s market price. Modern Portfolio Theory in their eyes is inadequate and should not be used to determine a reliable price or construct a profitable portfolio. Montier (2009) explains that in order for the CAPM to work, it must abide to a set of underlying assumptions which are at odds with reality. Fama and French (2004) show that returns predicted by the CAPM are not in line with the true returns during the period of 1928- 2003 They go as far as saying “we also warn students that despite its seductive simplicity, the CAPM’s empirical problems probably invalidate its use”. Malkiel (2003), a strong proponent of the EMF, admits that some market participants demonstrate less than rational behavior resulting in pricing irregularities and even predictable patterns in stock returns for short