Dampened Power Law: Reconciling the Tail Behavior of Financial Security Returns

This paper proposes a stylized model that reconciles several seemingly conflicting findings on financial security returns and option prices. The model is based on a pure jump Levy process, wherein the jump arrival rate obeys a power law dampened by an exponential function. The model allows for different degrees of dampening for positive and negative jumps, and also different pricing for upside and downside market risks. Calibration of the model to the S&P 500 index shows that the market charges only a moderate premium on upward index movements, but the maximally allowable premium on downward index movements.dampened power law; alpha-stable distribution; central limit theorem; upside movement; downside movement

Asset Pricing Under The Quadratic Class

We identify and characterize a class of term structure models where bond yields are quadratic functions of the state vector. We label this class the quadratic class and aim to lay a solid theoretical foundation for its future empirical application. We consider asset pricing in general and derivative pricing in particular under the quadratic class. We provide two general transform methods in pricing a wide variety of fixed income derivatives in closed or semi­closed form. We further illustrate how the quadratic model and the transform methods can be applied to more general settings.quadratic class; interest rates; term structure models; state price density; Markov process.

The Finite Moment Log Stable Process and Option Pricing

We document a surprising pattern in market prices of S&P 500 index options. When implied volatilities are graphed against a standard measure of moneyness, the implied volatility smirk does not flatten out as maturity increases up to the observable horizon of two years. This behavior contrasts sharply with the implications of many pricing models and with the asymptotic behavior implied by the central limit theorem (CLT). We develop a parsimonious model which deliberately violates the CLT assumptions and thus captures the observed behavior of the volatility smirk over the maturity horizon. Calibration exercises demonstrate its superior performance against several widely used alternatives.Volatility smirk; central limit theorem; Levy a­lpha-stable motion; self­similarity; option pricing.

Taking Positive Interest Rates Seriously

We present a dynamic term structure model in which interest rates of all maturities are bounded from below at zero. Positivity and continuity, combined with no arbitrage, result in only one functional form for the term structure with three sources of risk. One dynamic factor controls the level of the interest rate and follows a special two-parameter square-root process under the risk-neutral measure. The two parameters of the process determine the other two sources of risk and act as two static factors. This model has no other parameters to estimate and hence bears no other risks.Term structure, consistency, positivity, quadratic forms

Design and Estimation of Quadratic Term Structure Models

We consider the design and estimation of quadratic term structure models. We start with a list of stylized facts on interest rates and interest rate derivatives, classified into three layers: (1) general statistical properties, (2) forecasting relations, and (3) conditional dynamics. We then investigate the implications of each layer of property on model design and strive to establish a mapping between evidence and model structures. We calibrate a two­factor model that approximates these three layers of properties well, and illustrate how the model can be applied to pricing interest rate derivatives.quadratic model; term structure; positive interest rates; humps; expectation hy­pothesis; GMM; caps and floors.

Variance Risk Premia

We propose a direct and robust method for quantifying the variance risk premium on financial assets. We theoretically and numerically show that the risk-neutral expected value of the return variance, also known as the variance swap rate, is well approximated by the value of a particular portfolio of options. Ignoring the small approximation error, the difference between the realized variance and this synthetic variance swap rate quantifies the variance risk premium. Using a large options data set, we synthesize variance swap rates and investigate the historical behavior of variance risk premia on five stock indexes and 35 individual stocks.Stochastic volatility, variance risk premia, variance swap, volatility swap, option pricing, expectation hypothesis

Are Interest Rate Derivatives Spanned by the Term Structure of Interest Rates?

We investigate whether the same finite dimensional dynamic system spans both interest rates (the yield curve) and interest rate options (the implied volatility surface). We find that the options market exhibits factors independent of the underlying yield curve. While three common factors are adequate to capture the systematic movement of the yield curve, we need three additional factors to capture the movement of the implied volatility surface.Factors; principal component; LIBOR; swaps; swaptions; yield curve; implied volatility surface.

What Type of Process Underlies Options? A Simple Robust Test

We develop a simple robust test for the presence of continuous and discontinuous (jump) com­ponents in the price of an asset underlying an option. Our test examines the prices of at­the­money and out­of­the­money options as the option maturity approaches zero. We show that these prices converge to zero at speeds which depend upon whether the sample path of the underlying asset price process is purely continuous, purely discontinuous, or a mixture of both. By applying the test to S&P 500 index options data, we conclude that the sample path behavior of this index contains both a continuous component and a jump component. In particular, we find that while the pres­ence of the jump component varies strongly over time, the presence of the continuous component is constantly felt. We investigate the implications of the evidence for parametric model specifications.Jumps; continuous martingale; option pricing; Levy density; double tails; local time.

Stochastic Skew in Currency Options

We document the behavior of over-the-counter currency option prices across moneyness, maturity, and calendar time on two of the most actively traded currency pairs over the past eight years. We find that the risk-neutral distribution of currency returns is relatively symmetric on average. However, on any given date, the conditional currency return distribution can show strong asymmetry. This asymmetry varies greatly over time and often switch directions. We design and estimate a class of models that capture these unique features of the currency options prices and perform much better than traditional jump- diffusion stochastic volatility models.currency options, stochastic skew, time-changed Levy processes

What Constitutes a Good Model? An Analysis of Models for Mortgage Backed Securities

The U.S. agency mortgage backed securities (MBS) market is deep and highly liquid, yet modeling MBS is extremely challenging. This paper applies market participants' desired requirements for a good pricing model to MBS pricing models provided by six of the top MBS dealers. We find that five out of the six models fall short of the desired requirements. The five models are highly correlated, but less correlated with the best model, indicating potential herding among MBS analysts. The most undesirable property of the failed models is the high correlation with the underlying interest rate and options markets.Mortgage-backed securities, option-adjusted spreads, market efficiency