Testing calibration quality by means of backtesting is an integral part in the validation of credit rating systems. Against this background this paper provides a comprehensive overview of existing testing procedures. We study the procedures’ deficiencies theoretically and illustrate their impact empirically. Based on the insights gained therefrom, we develop enhanced hybrid testing procedures which turn out to be superior to the commonly applied methods. We also propose computationally efficient algorithms for our calibration tests. Finally, we are able to demonstrate empirically that our method outperforms existing tests in a scenario analysis using rating data of Moody’s.

We study IPO pricing in Germany to determine whether when-issued trading provides information that is useful for setting IPO offer prices, and whether such trading supplants bookbuilding as a source of information. We find that when-issued trading reveals relevant information for pricing IPOs, and that, once when-issued trading has begun, bookbuilding is not a source of costly information for pricing. But bookbuilding does not appear to be fully supplanted as a source of pricing information. We find evidence consistent with bookbuilding being used to gather information prior to the onset of when-issued trading.