i am trying to interpolate option prices for an option of Maturity T, Delta D and strike K from a list of available listed options. Intrinsic val is simple and what i really want to interpolate is the extrinsic value. So lets say I have a 1M and 2M listed option of delta D and strike K and want to interpolate price for 1.5M option. Having a linear interpolation will not be very successful here since the price term structure (extrinsic val) will not be a straight line. Moreover, it will be convex or concave depending on the delta. Could you suggest something which could make use of the greeks or other stuff from listed in order to get the extrinsic val of the desired mat.
Thanks
Thanks