Smile Modeling in the LIBOR Market Model Might Be Especially Closed Form Solutions, E.G
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University of Karlsruhe (TH) Chair of Statistics, Econometrics and Mathematical Finance (Professor Rachev) Diploma Thesis SMILE MODELING IN THE LIBOR MARKET MODEL submitted by: supervised by: Markus Meister Dr. Christian Fries Seckbacher Landstraße 45 (Dresdner Bank, Risk Control) 60389 Frankfurt am Main Dr. Christian Menn [email protected] (University of Karlsruhe) Frankfurt am Main, August 20, 2004 Contents List of Figures vii List of Tables viii Abbreviations and Notation ix I The LIBOR Market Model and the Volatility Smile 1 1 Introduction 2 2 The LIBOR Market Model 5 2.1 Yield Curve . 5 2.2 Volatility . 6 2.2.1 Black’s Formula for Caplets . 8 2.2.2 Term Structure of Volatility . 10 2.3 Correlation Matrix . 11 2.3.1 Black’s Formula for Swaptions . 13 i ii 2.3.2 A Closed Form Approximation for Swaptions . 14 2.3.3 Determining the Correlation Matrix . 16 2.3.4 Factor Reduction Techniques . 17 2.4 Deriving the Drift . 19 2.5 Monte Carlo Simulation . 22 2.6 Differences to Spot and Forward Rate Models . 24 3 The Volatility Smile 25 3.1 Reasons for the Smile . 26 3.2 Sample Data . 28 3.3 Requirements for a Good Model . 31 3.4 Calibration Techniques . 33 3.5 Overview over Different Basic Models . 34 II Basic Models 37 4 Local Volatility Models 38 4.1 Displaced Diffusion (DD) . 39 4.2 Constant Elasticity of Variance (CEV) . 42 4.3 Equivalence of DD and CEV . 46 4.4 General Properties . 49 4.5 Mixture of Lognormals . 50 4.6 Comparison of the Different Local Volatility Models . 55 iii 5 Uncertain Volatility Models 56 6 Stochastic Volatility Models 59 6.1 General Characteristics and Problems . 59 6.2 Andersen, Andreasen (2002) . 60 6.3 Joshi, Rebonato (2001) . 64 6.4 Wu, Zhang (2002) . 66 6.5 Comparison of the Different Stochastic Volatility Models . 71 7 Models with Jump Processes 73 7.1 General Characteristics and Problems . 73 7.2 Merton’s Fundament . 74 7.3 Glasserman, Kou (1999) . 77 7.4 Kou (1999) . 79 7.5 Glasserman, Merener (2001) . 84 7.6 Comparison of the Different Models with Jump Processes . 93 III Combined Models and Outlook 95 8 Comparison of the Different Basic Models 96 8.1 Self-Similar Volatility Smiles . 96 8.2 Conclusions from the Different Basic Models . 101 iv 9 Combined Models 104 9.1 Stochastic Volatility with Jump Processes and CEV . 105 9.2 Stochastic Volatility with DD . 110 10 Summary 121 Appendix I A Mathematical Methods II A.1 Determining the Implied Distribution from Market Prices . II A.2 Numerical Integration with Adaptive Step Size . IV A.3 Deriving a Closed-Form Solution to Riccati Equations with Piece- Wise Constant Coefficients . V A.4 Deriving the Partial Differential Equation for Heston’s Stochastic Volatility Model . VII A.5 Drawing the Random Jump Size for Glasserman, Merener (2001) . X A.6 Parameters for Jarrow, Li, Zhao (2002) . XI B Additional Figures XIII C Calibration Tables for SV and DD XX Bibliography XXIV Index XXXI List of Figures 3.1 Caplet Volatility Surface for e and US-$ . 29 3.2 Caplet Volatility Smiles for Different Expiries (e)......... 30 3.3 Swaption Volatility Smiles for Different Tenors (e)........ 31 3.4 Comparison of the Forward Rate Distribution between Market Data and a Flat Volatility Smile . 32 3.5 Model Overview . 36 4.1 Displaced Diffusion - Possible Volatility Smiles . 41 4.2 Market and Displaced Diffusion Implied Volatilities (e)...... 42 4.3 Constant Elasticity of Variance - Possible Volatility Smiles . 46 4.4 Market and Constant Elasticity of Variance Implied Volatilities (e) 47 4.5 Equivalence of DD and CEV . 48 4.6 Market and Mixture of Lognormals Implied Volatilities (e).... 52 4.7 Market and Extended Mixture of Lognormals Implied Volatilities (e).................................. 54 6.1 Market and Andersen/Andreasen’s Stochastic Volatility Model Implied Volatilities (e)....................... 64 6.2 Market and Wu/Zhang’s Stochastic Volatility Model Implied Volatilities (e)............................ 71 v vi 7.1 Market and Glasserman/Kou’s Jump Process Implied Volatilities (e).................................. 78 7.2 Comparison between Different Distributions for the Jump Size . 83 7.3 Market and Kou’s Jump Process Implied Volatilities (e)..... 84 7.4 Market and Glasserman/Merener’s Jump Process Implied Volatili- ties (e)............................... 88 7.5 Market and Glasserman/Merener’s Restricted Jump Process Im- plied Volatilities (e)........................ 93 8.1 Basic Models Calibrated to Sample Market Data . 98 8.2 Future Volatility Smiles Implied by the Local Volatility Model . 99 8.3 Future Volatility Smiles Implied by the Uncertain Volatility Model 100 8.4 Future Volatility Smiles Implied by the Stochastic Volatility Model 101 8.5 Future Volatility Smile Implied by the Jump Model . 102 9.1 Comparison between Different Expansions around the Volatility of Variance . 108 9.2 Market and Jarrow/Li/Zhao’s Combined Model Implied Volatili- ties (e)............................... 109 9.3 Market and SV & DD Model Implied Caplet Volatilities (e)... 112 9.4 Market and SV & DD Model Implied Swaption Volatilities (e).. 113 9.5 The Dependencies between the Swaption Implied Volatilities and the Parameters for the SV & DD Model . 117 9.6 Comparison between Market and Model Implied Volatilities in the SV & DD Model for a Caplet . 120 9.7 Comparison between Market and Model Implied Volatilities in the SV & DD Model for a Swaption . 120 vii B.1 Caplet Volatility Smiles for Different Expiries (US-$) . XIII B.2 Swaption Volatility Smiles for Different Tenors (US-$) . XIV B.3 Market and Displaced Diffusion Implied Volatilities (US-$) . XIV B.4 Market and Constant Elasticity of Variance Implied Volatilities (US-$) . XV B.5 Market and Mixture of Lognormals Implied Volatilities (US-$) . XV B.6 Market and Extended Mixture of Lognormals Implied Volatilities (US-$) . XVI B.7 Market and Andersen/Andreasen’s Stochastic Volatility Model Implied Volatilities (US-$) . XVI B.8 Market and Wu/Zhang’s Stochastic Volatility Model Implied Volatilities (US-$) . XVII B.9 Market and Glasserman/Kou’s Jump Process Implied Volatilities (US-$) . XVII B.10 Market and Kou’s Jump Process Implied Volatilities (US-$) . XVIII B.11 Market and SV & DD Model Implied Caplet Volatilities (US-$) . XVIII B.12 Market and SV & DD Model Implied Swaption Volatilities (US-$) XIX List of Tables 8.1 Comparison of the Basic Models and Their Characteristics . 103 C.1 Volatility and Skew Parameters for SV & DD . XX C.2 Bootstrapped Forward Rate Volatilities for SV & DD . XXI C.3 Optimized Forward Rate Volatilities for SV & DD . XXI C.4 Optimized Forward Rate Skews for SV & DD . XXII C.5 Differences between Volatility and Skew Parameters for the Swap- tion Smile . XXIII viii Abbreviations and Notation A(t) the asset or stock price at time t a the mean of the logarithm of the jump size (ln[J]) b the n × m matrix of the coefficients bik bik(t) the percentage volatility of the forward rate Li(t) coming from factor k as part of the total volatility ln[L/K]+ 1 v2 ln[L/K]− 1 v2 Φ 2 Φ 2 Bl(K,L,v) = L v − K v J the jump size of the forward rate K the strike of an option L(t,T,T + δ) forward rate at time t for the expiry(T)-maturity(T + δ) pair Li(t) L(t,Ti,Ti+1) LN (a,b) the lognormal distribution with parameters a and b for the underlying normal distribution N(a,b) h i ln K M the standardized moneyness of an option M = √Li(t) σi Ti−t m the expected percentage change of the forward rate because of one jump N (a,b) the Gaussian normal distribution with mean a and variance b NT the number of jump events up to time T NP the notional of an option O(xk) the residual error is smaller in absolute value than some constant times xk if x is close enough to 0 pi, j the probability of scenario j for forward rate Li(t) P(t,T + δ) the price of a discount bond at time t with maturity T + δ Payoff(Product)t the (expected) payoff of a derivative at time t ix ABBREVIATIONS AND NOTATION x Sr,s(t) the equilibrium swap rate at time t for a swap with the first reset date in Tr and the last payment in Ts s the volatility of the logarithm of the jump size (ln[J]) Xi the variable in the displaced diffusion approach that is lognormally distributed V the variance of the forward rate w the Brownian motion of the variance in the stochastic volatility models z(k) the Brownian motion of factor k zi the Brownian motion of the forward rate Li(t) with Pm dzi = k=1 bik(t)dz(k) zr,s the Brownian motion of the swap rate Sr,s(t) with σ Pm r,s,k(t) dzr,s = dz k=1 σr,s(t) (k) α the offset of the forward rate in the displaced diffusion approach β the skew parameter in the stochastic volatility models γ the parameter for the forward rate in the constant elasticity of variance approach δ the time distance between Ti and Ti+1 and therefore the tenor of a forward rate ε the volatility of variance κ the reversion speed to the reversion level of the variance λ the Poisson arrival rate of a jump process µi(t) the drift of the forward rate Li(t) ρ the correlation matrix of the forward rates ρi, j(t) the correlation between the forward rates Li(t) and L j(t) ρi,V (t) the correlation between the forward rate Li(t) and the variance V(t) ρ∞ the parameter determining the correlation between the first and the last forward rate σi(t) the volatility of the logarithm of the forward rate Li(t) σik(t) the volatility of the logarithm of the forward rate Li(t) coming from factor k σi(t;Li(t)) the local volatility of the forward rate Li(t) σr,s(t) the volatility of the logarithm of the swap rate Sr,s(t) ABBREVIATIONS AND NOTATION xi σr,s,k(t) the volatility of the logarithm