0000000000006605
AUTHOR
Steen Koekebakker
A Generalization of the Mean-Variance Analysis
In this paper we consider a decision maker whose utility function has a kink at the reference point with different functions below and above this reference point. We also suppose that the decision maker generally distorts the objective probabilities. First we show that the expected utility function of this decision maker can be approximated by a function of mean and partial moments of distribution. This "mean-partial moments" utility generalizes not only the mean-variance utility of Tobin and Markowitz, but also the mean-semivariance utility of Markowitz. Then, in the spirit of Arrow and Pratt, we derive an expression for a risk premium when risk is small. Our analysis shows that a decision…
Pricing of forwards and other derivatives in cointegrated commodity markets
Abstract We analyze cointegration in commodity markets, and propose a parametric class of pricing measures which preserves cointegration for forward prices with fixed time to maturity. We present explicit expressions for the term structure of volatility and correlation in the context of our spot price models based on continuous-time autoregressive moving average dynamics for the stationary components. The term structures have many interesting shapes, and we provide some empirical evidence from refined oil future prices at NYMEX defending our modeling idea. Motivated from these results, we present a cointegrated forward price dynamics using the Heath–Jarrow–Morton approach. In this setting, …
Modeling Term Structure Dynamics in the Nordic Electricity Swap Market
We analyze the daily returns of Nordic electricity swaps and identify significant risk premia in the short end of the market. On average, long positions in this part of the swap market yield negative returns. The daily returns are distinctively non-normal in terms of tail-fatness, but we find little evidence of asymmetry. We investigate if the flexible four-parameter class of normal inverse Gaussian (NIG) distributions can capture the observed stylized facts and find that this class of distributions offers a remarkably improved fit relative to the normal distribution. We also compare the fit with that of the four-parameter class of stable distributions; the NIG law outperforms the stable la…
Stochastic modeling of Supramax spot and forward freight rates
We conducted an empirical analysis of Supramax spot rates and propose a continuous time process to model the dynamics. The model incorporates features relevant for shipping freight rates, freight rate volatility that varies over time, sudden, big freight rate movements, and short-term, mean-reverting price trends. This suggests some degree of short-term predictability of Supramax spot rates, making shipping different from traditional asset markets, like stocks and currencies, and also most commodity markets. However, this does not imply that arbitrage profits are easily picked up in this market, as, financially speaking, spot freight rates are not traded assets. We instead focus on the rela…
Book Review: Derivatives and Risk Management in Shipping by Manolis D. Kavussanos and Ilias D. Visvikis
Derivatives and Risk Management in Shipping, by Manolis D. Kavussanos and Ilias D. Visvikis. Witherbys Publishing, 2006. 392pp. 10-ISBN: 1 85609 310 7; 13-ISBN: 978 1 85609 310 1
Multivariate modeling and analysis of regional ocean freight rates
Abstract In this paper, we propose a new multivariate model for the dynamics of regional ocean freight rates. We show that a cointegrated system of regional spot freight rates can be decomposed into a common non-stationary market factor and stationary regional deviations. The resulting integrated CAR process is new to the literature. By interpreting the common market factor as the global arithmetic average of the regional rates, both the market factor and the regional deviations are observable which simplifies the calibration of the model. Moreover, forward contracts on the market factor can be traded in the Forward Freight Agreement (FFA) market. We calibrate the model to historical spot r…
A Generalisation of the Mean-Variance Analysis
In this paper we consider a decision maker whose utility function has a kink at the reference point with different functions below and above this reference point. We also suppose that the decision maker generally distorts the objective probabilities. First we show that the expected utility function of this decision maker can be approximated by a function of mean and partial moments of distribution. This ‘mean-partial moments’ utility generalises not only mean-variance utility of Tobin and Markowitz, but also mean-semivariance utility of Markowitz. Then, in the spirit of Arrow and Pratt, we derive an expression for a risk premium when risk is small. Our analysis shows that a decision maker i…
THE CARMA INTEREST RATE MODEL
In this paper, we present a multi-factor continuous-time autoregressive moving-average (CARMA) model for the short and forward interest rates. This model is able to present an adequate statistical description of the short and forward rate dynamics. We show that this is a tractable term structure model and provides closed-form solutions to bond prices, yields, bond option prices, and the term structure of forward rate volatility. We demonstrate the capabilities of our model by calibrating it to a panel of spot rates and the empirical volatility of forward rates simultaneously, making the model consistent with both the spot rate dynamics and forward rate volatility structure.
Value based trading of real assets in shipping under stochastic freight rates
The article uses a real options valuation model with stochastic freight rates to investigate market efficiency and the economics of switching between the dry bulk and the tanker markets in international shipping. A dry bulk carrier is replaced with a tanker when the expected net present value of such a switch is optimal from a real options based decision rule. Depending on the development of the markets a reversal may take place later. The cost and demand parameters upon which the decisions to switch are made, including the stochastic characteristics of freight rates, are estimated from an empirical analysis that is updated every week throughout a 12-year time period from 1993 to 2005. The …
Portfolio performance evaluation with generalized Sharpe ratios: Beyond the mean and variance
The main purpose of this paper is to present a theoretically sound portfolio performance measure that takes into account higher moments of the distribution of returns. First, we perform a study of the investor's preferences to higher moments of distribution within expected utility theory and discuss the performance measurement. To illustrate the investor's preferences to higher moments and the computation of a performance measure, we provide an approximation analysis of the optimal capital allocation problem and derive a formula for the Sharpe ratio adjusted for skewness of distribution. This performance measure justifies the notion of the Generalized Sharpe Ratio (GSR) introduced by Hodges…
Stochastic dynamical modelling of spot freight rates
Based on empirical analysis of the Capesize and Panamax indices, we propose different continuous-time stochastic processes to model their dynamics. The models go beyond the standard geometric Brownian motion, and incorporate observed effects like heavy-tailed returns, stochastic volatility and memory. In particular, we suggest stochastic dynamics based on exponential Levy processes with normal inverse Gaussian distributed logarithmic returns. The Barndorff-Nielsen and Shephard stochastic volatility model is shown to capture time-varying volatility in the data. Finally, continuous-time autoregressive processes provide a class of models sufficiently rich to incorporate short-term persistence …
Warren Buffett versus Zvi Bodie: Should You Buy Or Sell Put Options?
Academics and investment professionals often disagree when it comes to investment advice. Legendary investor Warren Buffett is a proponent of time diversification and firmly believes that stocks are less risky in the long run. Therefore, he often sells long-term put options instead of buying them for portfolio protection. By contrast, the famous finance professor Zvi Bodie argues that time diversification is a fallacy and, therefore, his advice to fund managers is to buy long-term portfolio insurance. In this article, we consider the optimal portfolio choice problem for a loss-averse investor. First, we demonstrate that our loss-averse investor subscribes to the principle of time diversific…