Stock Picking in a “Fruit Fly Lab”
July 19, 2006 - Investing Expertise
Does a natural selection metaphor apply to stock picking models? In other words, can competition among a large set of dynamic models to mimic historical stock performance data evolve the most fit models? In their May 2006 paper entitled “Stock Selection – An Innovative Application of Genetic Programming Methodology”, Ying Becker, Peng Fei and Anna Lester address these questions by applying genetic programming to stock picking. Genetic programming enables the testing of a wide range of stock performance indicators in linear, non-linear and non-obvious combinations. The authors choose the S&P 500, excluding financials and utilities, as their universe of stocks and define two distinct types of stock-picking model fitness: (1) risk-adjusted outperformance compared to a traditional stock-picking model; and, (2) highest possible return independent of risk. They construct for comparison a traditional stock return forecasting model based on a linear combination of four composite factors: valuation, quality, analyst expectations and price. They use monthly data (65 variables for each of about 350 stocks) over the period January 1990 through December 2005 to create environments for model development and out-of-sample testing. They show that: Keep Reading