Some more details have been made available:
link- Tender offer will run from March 3 to March 30 with a possible extension. At least 67% has to be tendered.
- 500m reimbursement fee if the offer isn't succesful.
- R&D Newco will be financed by 420m CHF cash from Actelion, and a credit facility plus a convertible loan of 580m CHF from JNJ.
- first tranche of convertible loan (235m) will automatically convert in a 16% stake in R&D Newco. The remaining tranche (345m) is convertible in an additional 16% stake.
So R&D Newco starts out with ~655m cash and the second tranche of convertibles imply a valuation of ~2.1b. If you value the spinoff at $750m upside is roughly 7%. Looks great but I don't think I can handicap regulatory issues / medical trials very well so I only have a small position.