I was wounderingwondering whether the option implied probability density of the logreturnslog returns:
$x = \ln\left(\frac{S}{S_0}\right)$ with S the value of a certain stock, is always symmetric ?
I was asking myself this question because we model the "randomness" in the logreturnlog return with a Brownian motion which is symmetric around zero, which leads to a model of the form:
$dx_T = a(x,t)dt+b(x,t)dW_T$ with $W_T$ the Brownian motion. Where we simply have a drift where we superimpose a random walk.
In this kind of model there can't be a skewness, now I was wounderingwondering whether there were any models whichthat take skewness into account and if it's already been seen in the disstributiondistribution of the logreturns log returns?