hc costless collar andrea finished costless collar valuation see spreadsheets details checked bloomberg volatility assumption 100 days volatility around 50 since option 3 years volatility somewhat smaller put array calculations volatility ranges 20 60 questions please call bob lee zimin forwarded zimin lu hou ect 01 09 2001 09 02 bob lee enron 01 09 2001 08 48 zimin lu hou ect ect cc subject hc costless collar