Many times I received call from other company (new comer) for marketing purpose and telling me that you are holding demat account in sharekhan. They also offer less brokerage / promise for good service than sharekhan etc... I understand it is part of marketing. My question is How they come to know that I am holding demat account in sharekhan. From where they get this information, is sharekhan provide the detail ? I have also complaint in sharekhan customer care, but not received any reply.