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AN EXAMINATION OF PREDICTION MARKET EFFICIENCY: NBA CONTRACTS ON TRADESPORTS

Richard Borghesi

Abstract


In this paper I examine the absolute and relative price efficiency of NBA options listed on Tradesports.com.  I find that contracts within specific price bands are misvalued, but also demonstrate that this market is more efficient than is the market for NFL options.  Specifically, I show that contracts priced around $25 win (expire at $100) at a rate less than expected, while those priced around $75 win at a rate greater than expected.  The magnitudes of these deviations between prices and fundamental values are less than those in the NFL market.  Also, while prior theoretical work predicts that low-priced contracts should be overpriced, I instead find that NBA contracts priced near $2.50 win more frequently than expected.

I thank Rob Dougherty and Brijesh Patel for assistance with the NBA event data, and Leighton Vaughan Williams for meaningful suggestions throughout.  Any errors are strictly my own.


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References


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DOI: http://dx.doi.org/10.5750/jpm.v3i2.462

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