主 题: Malliavin Greeks without Malliavin Calculus
报告人: 陈南 博士 (香港中文大学)
时 间: 2007-10-29 下午 3:00 - 4:00
地 点: 理科一号楼 1560 
  
 We  derive  and  analyze  Monte  Carlo  estimators  of  price  sensitivities 
  
    (``Greeks\'\')  for  contingent  claims  priced  in  a  diffusion  model.    There     
  
 
  
    have  traditionally  been  two  categories  of  methods  for  estimating     
  
 
  
    sensitivities:  methods  that  differentiate  paths  and  methods  that     
  
 
  
    differentiate  densities.  A  more  recent  line  of  work  derives  estimators     
  
 
  
    through  Malliavin  calculus. 
  
 
  
    The  purpose  of  this  article  is  to  investigate  connections  between 
  
 
  
    Malliavin  estimators  and  the  more  traditional  and  elementary  pathwise  method 
  
 
  
    and  likelihood  ratio  method.    Malliavin  estimators  have  been  derived 
  
 
  
    directly  for  diffusion  processes,  but  implementation  typically  requires 
  
 
  
    simulation  of  a  discrete-time  approximation.    This  raises  the  question     
  
 
  
    of  whether  one  should  discretize  first  and  then  differentiate,  or     
  
 
  
    differentiate  first  and  then  discretize.  We  show  that  in  several     
  
 
  
    important  cases  the  first route  leads  to  the  same  estimators  found  through  Malliavin  calculus, but  using  only  elementary  techniques.  Time-averaging  of 
  
 
  
    multiple  estimators  emerges  as  a  key  feature  in  achieving  convergence 
  
 
  
    to  the  continuous-time  limit. 
  
 
  
    This  is  a  joint  work  with  Prof.  Paul  Glasserman  at  Columbia  University.