The Concentration Manifesto for Shorts
We were reading the great research that comes from our friends at Novus recently and saw a reference to a paper written by Della Corte, Kosowski, Rapanos (2019). This paper analyzes 1.7 million short positions from 585 managers that contributed to the European Union Short Disclosure Information dataset from 2012-2018. They found that highest quintile conviction shorts (P5 - as measured by position size) outperformed lowest quintile conviction shorts (P1). In fact, the highest conviction shorts were the only cohort that had a mean return that was negative on an absolute basis (positive contribution for shorts).
After applying a six-factor model, the alpha of a strategy going long the low conviction and short the high conviction had an alpha of 11%. Ideally, the results would show a gradual declination between P1 and P5, but P4 does not follow that trend. Nevertheless, there is a demonstrable skill in short selection for the largest position sizes and provides further support for the Concentration Manifesto.
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