Case analysis: expiry-day leverage in the Jane Street interim order

Use only the figures reported from SEBI's interim order of 3 July 2025 (M08 · 8.12 Case B and 9.12.2) and treat them as allegations. (a) On 17 Jan 2024 the group's index-options delta exposure reached −₹39,426.15 crore, against ₹5,372 crore of constituents and futures sold in Patch II. Ignoring gamma, what fall in Bank Nifty would produce the reported profit of ₹734.93 crore on the options alone? (b) Why does the ratio of option delta exposure to cash position matter for the incentive to move the index, and why is that ratio easiest to build on expiry day? (c) Explain, with the module's theory, how VWAP-based settlement over the last 30 minutes and intraday position limits change the economics of such a strategy.