HI,I have been stuck on this problem for some time,,I have a data base of ftse 100 options historical data. I would like extract the implied index and risk free rate for the data using put-call parity by running a regression on the put call parity for each day and maturity,, for each day I match each call and put that have the same expiry and strike !!!eg.Date_trade Strike Maturity (t) CLOSE_C CLOSE_P C -P2/01/2002 4825 16 392 11.5 380.52/01/2002 5075 16 196 41.5 154.52/01/2002 5125 16 160.5 54 106.52/01/2002 5175 16 110 68 422/01/2002 5225 16 84 70.5 13.52/01/2002 5275 16 73.5 96 -22.52/01/2002 5325 16 37 118 -812/01/2002 5425 16 16 188 -1722/01/2002 5075 44 267 79.5 187.52/01/2002 5225 44 168.5 138.5 302/01/2002 5275 44 137 148.5 -11.52/01/2002 4825 261 645 208.5 436.52/01/2002 5225 261 391.5 339.5 522/01/2002 6025 261 89.5 824.5 -735 C-P=S0-Xexp[-tr] for Maturity 16 S0 = 4812.673284 slope -0.918694482 r = 1.934537828 This does not seem right ,, am I missing something ???what is wrong,??? is it the data or my calculation !!!!!ThanksHabib