Hi Subhanshu,

While registering yourself for CAT exam you will find 3 options as:-

1.New candidate registration

2.Registered candidate login

3.Registration for non-iim institutions

So, it is pretty clear that if any candidate wishes to apply for both iim as well as non-iim institutions then they are required to register as both "new candidate" as well as "non-iim registration".

Because if you only registered usibg the new cabdidate option then you will be allowed to sit for iim's counsellings only and not for the non-iim's ones.

So, its upto you that how will be apply.

Good luck .