Wednesday, May 22, 2019

Option prices in Bates SVJ model?


In this [post] discussed the European put and call price formulas under the Heston Stochastic Volatility model.


There exists an important extension of Heston model to include diffusion jumps, known as Bates Stochastic Volatility Jump (SVJ) model, as referred to in this paper.


What are the option price formulas in SVJ model?




Answer



The Bates model is represented by the bivariate system of stochastic differential equations dSt=(rq)Stdt+vtStdW1(t)+StdNtdvt=κ(θvt)dt+σvtdW2(t)

where EQ[dW1(t)dW2(t)]=ρdt
and Nt is a compound Poisson process with intensity λ and independent jumps J with ln(1+J)˜ N(ln(1+β)12α2,α2)
The parameters β and α determine the distribution of the jumps and the Poisson process is assumed to be independent of the Wiener processes.By application of delta-hedging argument,we have Ut+12vtSt22US2+12σ2vt2Uv2+ρσvtSt2USv+(rqλˉk)StUS+κ(θvt)UvrU+IU=0(1)
where IU=λ0[U(Sξ,v,t)U(S,v,t)]g(ξ)dξ
g(ξ)=12παξe12α2(lnξm)2
m=ln(1+β)12α2
ˉk=e12α2+m1
It should be noted that closed-form solutions for vanilla-option payoff do exist but PIDE (1) is easily approximated by Numerical Methods.




close form solution


I edited my Answer for emcor.



  1. Dynamic of St under historical measure dStSt=(μλˉJ)dt+vtdW1(t)+JdN(t)dvt=κ(θvt)dt+σvtdW2(t),
    where EP[dW1(t)dW2(t)]=ρdt,
    Nt is a compound Poisson process with intensity λ and independent jumps J with ln(1+J)˜ N(ln(1+ˉJ)12α2,α2).
    The parameters ˉJ and α determine the distribution of the jumps and the Poisson process is assumed to be independent of the Wiener processes.

  2. Change measure: PQ dStSt=(rqλ¯J)dt+vtdWQ1(t)+JdN(t)dvt=κ(θvt)dt+σvtdWQ2(t),
    where EQ[dWQ1(t)dWQ2(t)]=ρdt
    κ=κ+ξ
    θ=κθκ+ξ,
    such that ξ is volatility market price and J=J+JEP[ΔJwJw]
    ˉJ=ˉJ+Cov(J,ΔJwJw)1+EP[ΔJwJw].
    Where ΔJwJw is random percentage jump conditional on a jump occurring and dJwJw is percentage shock in the absence of jump.

  3. Note that,when ξ=0 we have κ=κ and θ=θ. We set ξ=0, because when we estimate the risk-neutral parameters to price options we do not need to estimate ξ. Also, when ΔJw/Jw0 thus we have J=J and ˉJ=ˉJ.

  4. let xt=lnSt then C(t,St,vt,J,K,T)=StP1KerτP2
    where,for j=1,2 Pj(xt,vt;xT,lnK)=12+1π0Re(eiϕlnKfj(ϕ;t,x,v)iϕ)dϕfj(ϕ;vt,xt)=exp[Cj(τ,ϕ)+Dj(τ,ϕ)vt+iϕxt+Ξj]Ξj=λτ(1+κ)uj+12[(1+κ)ϕeα2(ujϕ+0.5ϕ2)1],
    such that Cj(τ,ϕ)=(rqλˉκ)ϕτκθτσ2(ρσϕβjγj)2κθτσ2ln(1+12(ρσϕβjγj)1eγjτγj)Dj(τ,ϕ)=2(ujϕ+12ϕ2)ρσϕβj+γj1+e1γjτ1e1γjτγj=(ρσϕβj)22σ2(ujϕ+0.5ϕ2)
    and u1=12,u2=12,β1=κρσ,β2=κ



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