It is advisable to conduct transactions through an intermediary as you need a trading member of a stock exchange if you intend to buy or sell any security on stock exchanges, maintain an account with a depository if you intend to hold securities in demat form, need to deposit money with a banker to an issue if you are subscribing to public issues. One also gets guidance while transacting through an intermediary. We should choose a SEBI registered intermediary, as he is accountable for its activities.