Investment timing,liquidity, and agency costs of debt

This paper examines the effect of debt and liquidity on corporate investment in a continuous-time framework. We show that stockholder–bondholder agency conflicts cause investment thresholds to be U-shaped in leverage and decreasing in liquidity. In the absence of tax effects, we derive the optimal level of liquid funds that eliminates agency costs by implementing the first-best investment policy for a given capital structure. In a second step we generalize the framework by introducing a tax advantage of debt, and we show that an interior solution for liquidity and capital structure optimally trades off tax benefits and agency costs of debt.     

Robust stock option plans

The main purpose of this paper is to address the issue of robustness of stock option plans, which is essential for reliable accounting valuations. The introduction of the accounting standards SFAS 123R and IFRS 2 for executive stock options has led to an important change. As companies are now forced to value their stock options at grant date for accounting purposes, the robustness of prices against the choice of certain valuation models and input parameters has become a very important issue. We address this issue by first analyzing certain building blocks of existing stock option plans with regard to their robustness properties. Based on our analysis, we then show how robustness of stock option plans can be achieved. The resulting stock option plans are both transparent in structure and reasonable in respect to the incentives they provide in order to increase shareholder value. We therefore conclude that stock options can be reliably expensed, if the corresponding plans are properly designed.     

The term structure of illiquidity premia

We investigate the term structure of bond market illiquidity premia and show that the term structure varies greatly over time. Short and long end are strictly separated suggesting that different economic factors drive different parts of the term structure. We propose a stylized theoretical model which implies that current trading needs of investors determine the short end. The long-term risk of being forced to liquidate bond positions determines the long end. Empirical evidence supports these predictions. While short-term liquidation risk captured by asset market volatilities drives the short end, the long end depends on the long-term economic outlook.     

Modelling jumps in electricity prices: theory and empirical evidence

Objective of this paper is to enhance the understanding of modelling jumps and to analyse the model risk based on the jump component in electricity markets. We provide a common modelling framework that allows to incorporate the main jump patterns observed in electricity spot prices and compare the effectiveness of different jump specifications. To this end, we calibrate the models to daily European Energy Exchange (EEX) market data through Markov Chain Monte Carlo based methods. To assess the quality of the estimated jump processes, we analyse their trajectorial and statistical properties. Moreover, even when the models are calibrated to a cross-section of derivative prices substantial model risk remains.      

An Empirical Comparison of Forward-Rate and Spot-Rate Models for Valuing Interest-Rate Options

Our main goal is to investigate the question of which interest-rate options valuation models are better suited to support the management of interest-rate risk. We use the German market to test seven spot-rate and forward-rate models with one and two factors for interest-rate warrants for the period from 1990 to 1993. We identify a one-factor forward-rate model and two spot-rate models with two factors that are not significantly outperformed by any of the other four models. Further rankings are possible if additional criteria are applied.     

Does modeling framework matter? A comparative study of structural and reduced-form models

This study provides a rigorous empirical comparison of structural and reduced-form credit risk frameworks. The literature differentiates between structural models that are based on modeling of the evolution of the balance sheet of the issuer, and reduced-form models that specify credit risk exogenously by a hazard rate process. Until now, there has been no common agreement in academia and practice on which model framework better captures credit risk. As major difference we focus on the discriminative modeling of the default time. In contrast to the previous literature, we calibrate both approaches to the same data set, apply comparable estimation techniques, and assess the out-of-sample prediction quality on the same time series of credit default swap prices. As our empirical implementations of both approaches rely on the same market information we are able to judge whether empirically the model structure itself makes an important difference. Interestingly, our study shows that the models’ prediction power are quite close on average indicating that for pricing purposes the modeling type does not greatly matter compared to the input data used. Still, the reduced-form approach outperforms the structural for investment-grade names and longer maturities. In contrast the structural approach performs better for shorter maturities and sub-investment grade names.     

Sovereign credit spreads

The paper develops a structural credit risk model to study sovereign credit risk and the dynamics of sovereign credit spreads. The model features endogenous default and recovery rates that both depend on the interaction between domestic output fluctuations and global macroeconomic conditions. We show that sovereigns choose to default at higher levels of economic output once global macroeconomic conditions are bad. This yields to default rates and credit spreads that are substantially higher compared to normal times. We derive closed-form expressions for sovereign debt values and default times and focus on the dynamics of sovereign credit spreads. As opposed to standard theories of sovereign debt, this paper’s structural model generates much richer default patterns and non-linearities through regime-shifts in the global macroeconomic environment. Moreover, changes in the global environment reveal the interconnectedness of the financial system.     

Employee stock options with performance conditions: do commonly used valuation heuristics work?

Valuation heuristics are widely used to value traditional time vesting option plans. This study analyses if these heuristics also qualify for valuing performance vesting plans. We examine performance conditions tied to the underlying stock, the stock's performance relative to a stock index, and an earnings measure. The differences between the approximated option values and the values assuming optimal exercise are overall smaller with the performance conditions than without them. In particular, this result holds when the heuristic exercise assumptions are based on the case without performance conditions, which is a considerable simplification in practice.     

Trading Credit Default Swaps via Interdealer Brokers

Credit default swaps (CDSs) are among the most successful financial innovations of recent years, which is reflected in the rapidly expanding market. CDS trading occurs in the over-the-counter market, which relies heavily on broker intermediation to arrange trades. We provide empirical evidence that liquidity in the voice brokered market varies with the particulars of the CDS contracts and that the differences in market structure is reflected in the costs of liquidity. Moreover, the brokered and direct interdealer trading markets seem to be well integrated; thus the higher liquidity costs in the brokered market may reflect the value of intermediation. Hybrid market structures, which combine voice brokerage with an electronic platform, are discussed as a viable alternative to fully automated trading systems.

Risk structure of interest rates: an empirical analysis for Deutschemark‐denominated bonds

This paper empirically studies the risk structure of interest rates for Deutschemark‐denominated bonds. For this purpose, we estimate term structures of interest rates using the parsimonious fitting function of Nelson and Siegel (1987) for virtually risk free Government bonds and five different rating categories classified by Moody's ratings (Aaa, Aa, A, Baa, Ba). The sample period covers the time interval from July 1990 to December 1996. We investigate the pricing errors resulting from our estimation procedure and analyse credit spreads over the term structure of Government bonds.