New Delhi, July 4 -- The Securities and Exchange Board of India (Sebi) has barred four entities of the Jane Street Group from accessing the Indian securities market and impounded Rs.4,000 crore in what it termed as illegal gains from prima facie fraudulent and manipulative trades in index options.

In a detailed 105-page interim order, Sebi accused the global proprietary trading firm of deploying large-scale, expiry-centric strategies on at least 18 trading days-15 involving Bank Nifty and three involving Nifty-where the group allegedly distorted market prices through "sharp, large and aggressive interventions" in the cash and derivatives segments.

According to the order, the Jane Street Group-through its Indian and foreign affiliates-ra...