Established in Aug 1999, The New York-headquartered Jane Street has offices across the world. In June 2025, one of its co-founders was alleged to have financed a coup to topple the govt in South Sudan. The person then said he was duped into funding the coup. Sam Bankman-Fried, once the poster boy of the crypto world and now a convicted fraudster, once worked at Jane St.What led to Sebi’s actions?Four Jane St entities operated in India as registered foreign portfolio investors. The regulator banned the four entities from the market. Sebi also asked the entities to jointly disgorge illegal gains worth nearly Rs 4,850 crore. Sebi said Jane St had used two key strategies to manipulate the domestic stocks and futures & options (F&O) markets to make illegal gains over several years.

How did Jane St manipulate stocks?One of the strategies was to aggressively buy Bank Nifty’s constituent stocks and futures in the morning. At the same time, it would buy put options on the index. In the afternoon, it would sell stocks bought in the morning. This selling pushed up prices of options on Bank Nifty, which the fund had bought in the morning. Once put option prices rose, those were sold to make huge profits. The other strategy was concentrated selling or buying of Nifty index options in the last two hours of the expiry day to swing index levels to profit from such trades.So, what happens next?The fund has been asked to present its side of the case to Sebi within 21 days. Sebi is expected to expand the scope of its investigations into the trading operations of Jane St in India. The interim order focuses on the Jan 2023 to March 2025 period. The regulator is also expected to investigate if manipulative strategies were used in other indices and in BSE’s segments.