India's Securities and Exchange Board (SEBI) has temporarily barred U.S.-based trading firm Jane Street Group from accessing the country's securities market following an investigation into alleged market manipulation. SEBI's interim order accuses Jane Street of manipulating the Bank Nifty and Nifty 50 index derivatives, particularly on expiry days, to generate unlawful gains estimated at approximately ₹4,843 crore ($567 million). The regulator has directed the freezing of Jane Street's accounts and instructed entities linked to the case to deposit the alleged unlawful profits in escrow accounts. Jane Street reportedly made over ₹36,500 crore in profits from trading in India over the past two years, with the firm generating $4.3 billion in trading gains in the country during that period. SEBI's probe has revealed that Jane Street used strategies involving expiry-day index closing manipulations and breached foreign portfolio investor (FPI) rules through its India entity. The investigation is ongoing, with SEBI expanding its scope to examine trades across other indices and exchanges. Jane Street has contested the charges, describing its trading practices as basic index arbitrage and calling SEBI's allegations "inflammatory" and based on misunderstandings. The ban is considered one of the most stringent actions taken by Indian regulators against a foreign trading firm. The move has raised concerns about potential impacts on liquidity and volumes in India's derivatives market, although SEBI sources suggest it will aid responsible investing and capital formation. Meanwhile, a SEBI study highlighted that 91% of retail traders in India's equity derivatives segment incurred losses totaling over ₹1 lakh crore ($12.2 billion) in fiscal year 2025, underscoring the risks faced by individual investors in the market.