Attribution of hedge fund returns using a Kalman filter

Hedge funds offer attractive investment possibilities because they engage in investment styles and opportunity sets which – because they are different from traditional asset class funds – generate different risk exposures. Conventional wisdom holds that hedge funds add value and provide unique investment opportunities because of their ability to invest in disparate risk exposures, and via the manager’s skill in selecting stocks and timing the market. In this article, a Kalman filter is used to decompose the time series of hedge fund returns into market timing and stock selection factors to establish whether fund managers really do generate statistically significant abnormal profits. Compelling evidence supports an alternative interpretation for the market timing return constituent. This work represents the first time the Kalman filter has been used to extract a time series of the capital asset pricing model’s dynamic variables for determining return component magnitudes.