Does Zerodha & other brokerages extract, sell, or use our order details for their benefit which can be disadvantageous to us?
Any SEBI regulations preventing this?
Yes, They can do this but manually It will take so much Time.
Stock Brokers Deals with Millions Of Orders Per seconds for Tracking some specific Stock or Price or details They will Need A Very smart Artificial intelligence System and Real Time Algorithms.
Unlike in the US markets or most developed markets, there is no concept of dark pools or selling order flow in India. When you place an order, it is placed on the exchange directly. So none of what you are saying is really possible here, especially anything that could be disadvantageous to the trader.
But say if you were trading in US with a brokerage, the order you place could very well be executed with someone like a Citadel instead of on the exchange. The broker who sent the order to citadel, could make some commission by selling this order flow.