Why do we need a broker to trade the Stock markets?

As per SEBI guidelines, an individual cannot trades directly through an Exchange. Every individual who wish to trade has to go through a Member (broker) who is registered with exchange.

An Individual who is has huge portfolio and not willing to revile his portfolio, can get himself register on exchange first and then trade for himself, but there is lot if cost involved in it.

Normal retail trade will not be able to afford the cost involved in registering with exchange plus Member also has to appoint a clearing and settlement member to clear the trades through exchange.

Apart from this a broker provides added facilities like Margin funding, Cover order and guarantee your settlement with exchange in case the counter party is defaulted etc.

I think this will give you an idea why people trade through broker.