Jane Street in India: arbitrage or market manipulation?

Research methodology This case is based primarily on secondary data sources, including regulatory orders and communications issued by the Securities and Exchange Board of India (SEBI) and the National Stock Exchange (NSE), along with publicly available reports from financial news platforms such as Bloomberg, The Economic Times, Business Today, etc. These sources were used to reconstruct the sequence of events, regulatory concerns and market reactions relating to Jane Street’s trading activity in Indian index options. Given the proprietary nature of algorithmic trading strategies and the absence of direct access to firm-level internal data, no primary interviews were conducted. The case relies on triangulation across multiple credible public sources to ensure factual consistency. Case overview/synopsis In July 2025, Jane Street Group (JS Group), a leading high-frequency trading firm, found itself at the centre of regulatory scrutiny in India following interim restrictions imposed by the SEBI. The regulator alleged that certain derivatives trading strategies employed by the firm—particularly around index options expiry—were structured in a manner that influenced price movements in underlying securities and generated substantial gains. Over a relatively short period, the JS Group reported significant profits in index options while incurring losses in cash and futures segments, raising questions about the intent and design of its trading strategies. SEBI’s interim order required the firm to deposit approximately ₹48.44 billion, characterised as unlawful gains, and imposed restrictions on its market participation pending further investigation. The developments placed the JS Group at a critical inflection point. The firm faced the challenge of responding to regulatory action that had both financial and reputational implications, while continuing to defend its trading approach as legitimate arbitrage within the existing market framework. Complexity academic level This case is suitable for courses in corporate governance, derivatives, financial/capital markets or market regulation at the undergraduate, graduate and executive/professional development levels.