My ballpark numbers for the CESC demerger are as follows:
CESC (existing power business) - 12,500 - 16,500 cr. FY 17 PAT of 750 cr x 10% growth assumed for FY18 x 15-20 PE. The distribution company can actually be re-rated at more than 20PE as it is the only listed discom. The genco may be at the 12-15 PE range.
Spencers - 3300 cr. (2200 cr - 4400cr) FY 17 is 2000 cr x 10% growth x 1.5x Price/Sales (1-2x P/S)
CESC Ventures - 1000 cr. 55% of FSL marketcap of 2300 cr is about 1250 cr. Holding co discount of 30% would give about 900 cr. Add another 100 crs for other businesses liek Quest Mall, Real Estate etc
FY18E market cap for me is around 18,000. Current market cap is 13,000 cr.
Disclaimer: I may be wrong and my calculations. I have a vested interest in CESC. I am currently invested.