Which subjects to choose for pursuing my PhD in commerce?

First of all, decide from which university you want to pursue your PhD. Select a good institute where the commerce department is very famous and world-class. Know the procedure for applying for admission to that course in that institute.

Then try to contact a professor in that university and have a detailed discussion regarding your subjects and your experience and ask his suggestion to select the subject of your research. The subject should have a connection to your experience and to the subject you studied.

Similarly, you can discuss this subject with other people who are working in similar line so that they may also come out with their experience and suggestions which will help you select a subject.

There are many subjects related to the management of various organisations and tod decide on the best management policies. HR is also a very green subject where you will have a lot of scopes to work on the mindset of the people and how to bring different people with different mindsets to a common understanding on a common platform.

You have done your Masters in commerce and that is your core area. It makes sense to do PhD in commerce related subject only as you would be able to comprehend the research challenge better in this arena rather going in an unknown and alien territory. Commerce has evolved in a big area and there are so many topics here which are of perpetual interest as well as important in the contemporary financial scenario. Being a company secretary you are much inclined to do research in company law or related category but not getting a good guide and university to allow for that or guide for that.

What I would suggest is you have to talk to some eminent professors in this matter who are guiding the students of commerce for PhD and they may give you some valuable suggestion in this matter. If you are much inclined to choose a subject related to company law only then you might have to go to a subject which covers it but does not name it. It might look a bit cryptic what I am telling but there are some topics which do not mention law in the heading but they mean it when we go through the contents. So regulatory frameworks in commercial and business world are full of such topics and as I said a good guide can give some clues in this direction. If you get hold of some satisfying topics as per your ambition then you can try to get admission in PhD.

Some of the categories where company law and other regulations are automatically incorporated are - Public Administration, International business etc. One can search some good topics in them.

Since you have done your Masters in commerce, you are entitled to go ahead for the Ph.D in the commerce stream. There exists a lot of scopes in the arena of commerce such as Finance, Accounting, Cost - cutting drives and other scenarios. You can yourself judge the fields fascinating you in the area of commerce.
If you are still perplexed in going ahead in your venture, meet some professor having sufficient experience in handling the candidates perusing for Ph.D in commerce. He may suggest you some core areas which if undertaken for Ph.D would benifit you.
Considering that you are interested for the company law and still you have a passion for it but the heading of thesis project should not have any specific name relating to company law since that will violate the norm of the NET and your commerce stream with which you have done your post graduation.
To resolve this complex issue, you will have to approach a group of eminent professors assisting the aspirants to carry out research by being guides of the aspirants. They can suggest you some topics which may be intermediate between the two domains( commerce and company law). Your guide would suggest you how sometimes company law converts to commercial angle and accordingly you can undertake such a project. Of course, it is a mind boggling exercise for you but not for the able guides providing you very decisive solution.
International business is one of the domains of the company law fitting to your research activity and for which a serious negotiation is required to be undertaken with your guide for the persual of thesis.

Company law and secretary is a good course to pursue a career. Go through this link company secretary to get a clear picture about, which colleges have this course.