Why Zerodha is not allowing to buy ST category shares?
Because these are useless stocks and in certain stocks 100% of your margin will be blocked. Check this post for more
ST category stocks in Stage 2 or above require an additional surveillance deposit and I don’t think the depository has the provision for blocking additional deposits.
Excess volatility is what market looks for and trader must be aware of risk. Zerodha is harming individual by blocking such shares. I know many company are making profit and are still in surveillance while those making huge loss are trading in regular session. Zerodha should let customer decide instead of blocking securities.