Whilst it’s good to look sum of parts valuation, I would like to recall the unwinding or merger of Aditya Birla nuvo into Grasim.
The minority investors lost heavily as for no reason the 100% owned subsidiary of Aditya Birla Nuvo - Aditya Birla Capital (ABC) , ownership was first forcefully merged into Grasim (by way of some preference shares and some other instruments) thus giving only (if memory serves right) less than 40% of ABC. In effect promoter family increased their ownership into ABC at the cost of minorities.
While previously when Aditya Birla Nuvo demerged Aditya Birla Fashion, the effective ownership mirrored that of Aditya Birla Nuvo, hence neither any reward or cheating the minorities happened in Aditya Birla Fashion demerger.
Thus one need not think that ABC ownership of all it’s subsidiary and their gains would be rightfully shared with minorities.