Profitaker,
"Depends how stocks A & B were correlated"
Mathematically speaking, I am somewhat retarded. I'm guessing that "+1" means if X moves +1, Y moves +1 (and I stand corrected).
How do you derive the 19.12% figure?
How is the "implied index correlation (IIC)" determined (please use my examples)?
Re your FTSE IIC of 0.44, does this mean that for a 1% change in the IV of the constituents, the FTSE IV will change + 0.44%?
If this is a lack of 1:1 correlation, it may be due to the lack of options on some constituents and unwittingly, you may have saved me an awful lot of work â if no option is traded, then extrapolation becomes increasingly problematic(al?).
Another problem is contiguous data. Once an initial IV has been determined, higher/lower volatility is apparent from the premiums (or premia if you want to be pedantic). But to actually nail the IV's of the sum of the constituents and index at the point of execution may be a nightmare â unless it is blatant (then again, I've always thought, if you see an arbitrage opportunity, ignore it because it doesn't exist) .
Alternative potential candidates â I haven't checked â are DAX, CAC, SMI and DJ Euro Stoxx.
Do you use any software. I write my own, inspired by a product called Schwartzatron by Reuters. At the time (1990) they were charging £20,000 pa just to rent. And round the same time, an article in the Wall Stret Journal mentioned a product called Shark used by traders at Goldman Sachs.
Are you in the UK (where)? I'm in a sleepy fishing village called Manchester.
Rosy2,
Using my examples, obtain the eigenvalues and explain what they are/mean; also explain why they would provide a better insight than the weightings as stated. Show all workings, and please keep it simple.
IV Trader,
I'm just trying to establish the theoretical basis. It may never happen; not all the conditions of Black-Scholes are fully met but it is still used as a (plain vanilla) starting point.
I'm not looking to determine the index IV from the constituent's IV's â as you say, skew (smirk and smile) may throw that out of the window. Further, the constituents would exhibit skew, etc. Who wants to be a quant?
Grant.