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436
Testing ContinuousTime Models of the Spot Interest Rate
 Review of Financial Studies
, 1996
"... Different continuoustime models for interest rates coexist in the literature. We test parametric models by comparing their implied parametric density to the same density estimated nonparametrically. We do not replace the continuoustime model by discrete approximations, even though the data are rec ..."
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Cited by 302 (10 self)
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Different continuoustime models for interest rates coexist in the literature. We test parametric models by comparing their implied parametric density to the same density estimated nonparametrically. We do not replace the continuoustime model by discrete approximations, even though the data are recorded at discrete intervals. The principal source of rejection of existing models is the strong nonlinearity of the drift. Around its mean, where the drift is essentially zero, the spot rate behaves like a random walk. The drift then meanreverts strongly when far away from the mean. The volatility is higher when away from the mean. The continuoustime financial theory has developed extensive tools to price derivative securities when the underlying traded asset(s) or nontraded factor(s) follow stochastic differential equations [see Merton (1990) for examples]. However, as a practical matter, how to specify an appropriate stochastic differential equation is for the most part an unanswered question. For example, many different continuoustime The comments and suggestions of Kerry Back (the editor) and an anonymous referee were very helpful. I am also grateful to George Constantinides,
The Asymptotic Elasticity of Utility Functions and Optimal Investment in Incomplete Markets
 Annals of Applied Probability
, 1997
"... . The paper studies the problem of maximizing the expected utility of terminal wealth in the framework of a general incomplete semimartingale model of a financial market. We show that the necessary and sufficient condition on a utility function for the validity of several key assertions of the theor ..."
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Cited by 261 (17 self)
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. The paper studies the problem of maximizing the expected utility of terminal wealth in the framework of a general incomplete semimartingale model of a financial market. We show that the necessary and sufficient condition on a utility function for the validity of several key assertions of the theory to hold true is the requirement that the asymptotic elasticity of the utility function is strictly less then one. 1. Introduction A basic problem of mathematical finance is the problem of an economic agent, who invests in a financial market so as to maximize the expected utility of his terminal wealth. In the framework of a continuoustime model the problem was studied for the first time by R. Merton in two seminal papers [27] and [28] (see also [29] as well as [32] for a treatment of the discrete time case). Using the methods of stochastic optimal control Merton derived a nonlinear partial differential equation (Bellman equation) for the value function of the optimization problem. He al...
A Nonparametric Model of Term Structure Dynamics and the Market Price of Interest Rate Risk
, 1997
"... This article presents a technique for nonparametrically estimating continuoustime di#usion processes which are observed at discrete intervals. We illustrate the methodology by using daily three and six month Treasury Bill data, from January 1965 to July 1995, to estimate the drift and di#usion of t ..."
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Cited by 210 (5 self)
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This article presents a technique for nonparametrically estimating continuoustime di#usion processes which are observed at discrete intervals. We illustrate the methodology by using daily three and six month Treasury Bill data, from January 1965 to July 1995, to estimate the drift and di#usion of the short rate, and the market price of interest rate risk. While the estimated di#usion is similar to that estimated by Chan, Karolyi, Longsta# and Sanders (1992), there is evidence of substantial nonlinearity in the drift. This is close to zero for low and medium interest rates, but mean reversion increases sharply at higher interest rates.
Term Structure of Interest Rates with Regime Shifts
 Journal of Finance
, 2002
"... We develop a term structure model where the short interest rate and the market price of risks are subject to discrete regime shifts. Empirical evidence from efficient method of moments estimation provides considerable support for the regime shifts model. Standard models, which include affine specifi ..."
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Cited by 122 (2 self)
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We develop a term structure model where the short interest rate and the market price of risks are subject to discrete regime shifts. Empirical evidence from efficient method of moments estimation provides considerable support for the regime shifts model. Standard models, which include affine specifications with up to three factors, are sharply rejected in the data. Our diagnostics show that only the regime shifts model can account for the welldocumented violations of the expectations hypothesis, the observed conditional volatility, and the conditional correlation across yields. We find that regimes are intimately related to business cycles. MANY PAPERS DOCUMENT THAT THE UNIVARIATE short interest rate process can be reasonably well modeled in the time series as a regime switching process ~see Hamilton ~1988!, Garcia and Perron ~1996!!. In addition to this statistical evidence, there are economic reasons as well to believe that regime shifts are important to understanding the behavior of the entire yield curve. For example, business cycle expansion and contraction “regimes ” potentially
Catching Up with the Joneses: Heterogeneous Preferences and the Dynamics of Asset Prices
, 2001
"... ..."
Optimal investment policies for a firm with a random risk process: Exponential utility and minimizing the probability of ruin
 Math. Oper. Res
, 1995
"... We consider a rm that is faced with an uncontrollable stochastic cash ow, or random risk process. There is one investment opportunity, a risky stock, and we study the optimal investment decision for such rms. There is a fundamental incompleteness in the market, in that the risk to the investor of go ..."
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Cited by 70 (3 self)
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We consider a rm that is faced with an uncontrollable stochastic cash ow, or random risk process. There is one investment opportunity, a risky stock, and we study the optimal investment decision for such rms. There is a fundamental incompleteness in the market, in that the risk to the investor of going bankrupt can not be eliminated under any investment strategy, since the random risk process ensures that there is always a positive probability of ruin (bankruptcy). We therefore focus on obtaining investment strategies which are optimal in the sense of minimizing the risk of ruin. In particular, we solve for the strategy that maximizes the probability ofachieving a given upper wealth level before hitting a given lower level. This policy also minimizes the probability of ruin. We provethat when there is no riskfree interest rate, this policy is equivalent to the policy that maximizes utility fromterminalwealth, for a xed terminal time, when the rm has an exponential utility function. This validates a longstanding conjecture about the relation between minimizing probability of ruin and exponential utility. When there is a positive riskfree interest rate, the conjecture is shown to be false. Key words: Stochastic control � portfolio theory � di usions � Brownian motion � incomplete markets � insurance � Ruin theory � optimal gambling � smoothpasting � HamiltonJacobiBellman equations.
Jumps in financial markets: A new nonparametric test and jump clustering
, 2007
"... This article introduces a new nonparametric test to detect jump arrival times and realized jump sizes in asset prices up to the intraday level. We demonstrate that the likelihood of misclassification of jumps becomes negligible when we use highfrequency returns. Using our test, we examine jump dyn ..."
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Cited by 67 (4 self)
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This article introduces a new nonparametric test to detect jump arrival times and realized jump sizes in asset prices up to the intraday level. We demonstrate that the likelihood of misclassification of jumps becomes negligible when we use highfrequency returns. Using our test, we examine jump dynamics and their distributions in the U.S. equity markets. The results show that individual stock jumps are associated with prescheduled earnings announcements and other companyspecific news events. Additionally, S&P 500 Index jumps are associated with general market news announcements. This suggests different pricing models for individual equity options versus index options. (JEL G12, G22, G14) Financial markets sometimes generate significant discontinuities, socalled jumps, in financial variables. A number of recent empirical and theoretical studies proved the existence of jumps and their substantial impact on financial management, from portfolio and risk management to option and bond pricing
Optimal Dynamic Portfolio Selection: MultiPeriod MeanVariance Formulation
 Math. Finance
, 1998
"... The meanvariance formulation by Markowitz in 1950s and its analytical solution by Merton in 1972 paved a foundation for modern portfolio selection analysis in single period. This paper considers an analytical optimal solution to the meanvariance formulation in multiperiod portfolio selection. Spec ..."
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Cited by 60 (3 self)
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The meanvariance formulation by Markowitz in 1950s and its analytical solution by Merton in 1972 paved a foundation for modern portfolio selection analysis in single period. This paper considers an analytical optimal solution to the meanvariance formulation in multiperiod portfolio selection. Specifically, analytical optimal portfolio policy and analytical expression of the meanvariance efficient frontier are derived in this paper for the multiperiod meanvariance formulation. An efficient algorithm is also proposed in this paper in finding an optimal portfolio policy to maximize a utility function of the expected value and the variance of the terminal wealth. Key Words: Multiperiod portfolio selection, multiperiod meanvariance formulation, utility function. This research was partially supported by the Research Grants Council of Hong Kong, grant no. CUHK 4130/97E. The authors very much appreciate the constructive comments from Professor Stanley R. Pliska. y Author to whom a...
Multifractality in Asset Returns: Theory and Evidence
 REVIEW OF ECONOMICS AND STATISTICS
, 2001
"... This paper investigates the Multifractal Model of Asset Returns, a class of continuoustime processes that incorporate the thick tails and volatility persistence exhibited by many financial time series. The simplest version of the model compounds a Brownian Motion with a multifractal timedeformatio ..."
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Cited by 57 (6 self)
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This paper investigates the Multifractal Model of Asset Returns, a class of continuoustime processes that incorporate the thick tails and volatility persistence exhibited by many financial time series. The simplest version of the model compounds a Brownian Motion with a multifractal timedeformation process. Prices follow a semimartingale, which precludes arbitrage in a standard twoasset economy. Volatility has long memory, and the highest finite moments of returns can take any value greater than two. The local variability of the process is highly heterogeneous, and is usefully characterized by the local Hölder exponent at every instant. In contrast with earlier processes, this exponent takes a continuum of values in any time interval. The model also predicts that the moments of returns vary as a power law of the time horizon. We confirm this property for Deutsche Mark/U.S. Dollar exchange rates and several equity series. We then develop an estimator, and infer a parsimo...