Finally, the fund failed to outperform both the SPY and OEF in terms
of traditional
measures,
i.e. the annualized return,
volatility, alpha and beta, or Sharpe and Sortino ratios:
Ben Dor, Dynkin, Hyman, Houweling, Leeuwen, and Penninga (2007) demonstrate that spread changes are proportional to the level
of spreads,
i.e., the
volatility of percentage spread change is much more stable than absolute spread
volatility, and therefore they propose that the better
measure of exposure to credit risk is not the contribution to spread duration, but the contribution to DTS.