I have a Kotak Securities demat account in India, which I have not operated since November 2015. It is linked to a Kotak Mahindra Bank savings account which has ZERO balance. What will happen if I don't close and use it at all?
Most of the demat accounts in India have an annual fees, which they expect you to pay. If you fail to pay the fees, they would bar you from trading, and your account balance could go in negative. Since there is no balance in your linked account too, the linked savings account may be in overdraft (if it has the overdraft facility, that is).
It is advisable to close the demat account which is not used to avoid any unnecessary charges and interest.