Demergeing is not always wealth unlocking excercise.
1. Only those demergers creates huge benifits to minority shareholders, where demerged entity is a holding company.
2. Demerger of companies operating in sectors which fetch higher PE also creates values. But nothing near to point 1.
3. None of above 1 or 2.
RIL demerger belong to 1. In which RCL, RCol and REL was holding companies, their balance sheet was not part of RIL. So demerger does not hit RIL atall.
GE Shipping demerger comes under 2. Where oil rig biz will fetch higher PE than shipping. In this case all profits were part of original GE, it means after demerger, parent company will be HIT.
Triveni demerger belong to 3. Where engineering division is contributing to balance sheet and PE of seperate company will also be similer.
In near future, one can expect many more demerger. So, one need to rate against above 3 points.