Part 3: Jane Street in India – A Case Study in Expiry-Day Manipulation

What Jane Street Did (According to SEBI) Between Jan 2023 and Mar 2025: Jane Street executed large index trades on 18 separate options expiry days. Every time, a clear pattern emerged: Morning: Buy index constituents in large volumes—both stocks and futures—driving the index up. Mid-Day: Open large bearish derivative positions (puts, short futures). Afternoon: Offload index buys, reversing the price trend and causing a dip just before market close. Result: Losses in the cash/futures book, but huge profits from the well-timed options. This pattern mimicked a reverse pump-and-dump, tied intricately to the way Indian indices settle options at close prices. Take Jan 17, 2024 as an example: ₹4,370 cr (≈$525M) pumped into Bank Nifty stocks and futures by 11:47 AM. Then, Jane Street shorted the market via options. Price was driven back down as positions were unwound. Net result: Derivative profits: ₹735 cr Cash market losses: ₹62 cr Pure arbitrage via manipulation: ₹673 cr profit in one day (Livemint). This same strategy allegedly netted them over ₹36,500 cr (~$4.3 billion) across the expiry sessions. The Jan 17 Playbook – And the Bigger Picture On Jan 17, 2024, Jane Street allegedly: Jan 17 Example: How It Worked Jane Street: Bought ₹4,370 cr in Bank Nifty stocks/futures early. Opened short options positions midday. Sold off stocks, pushing prices down by close. Net gain: ₹735 cr in options profits ₹62 cr in cash/futures losses → ₹673 cr profit in one day This strategy was used across 18 expiry days, generating over ₹36,500 cr (~$4.3B). 🧠 SEBI’s Findings SEBI found: Repeated expiry-day trades timed to influence index closings. Patterns driven by algos, not market fundamentals. Clear intent to manipulate settlement prices. ⚖️ Outcome ₹4,843 cr seized, Jane Street barred from Indian markets. Probe widened to include brokers and clearing firms. A clear signal: Even elite firms face consequences for price manipulation.