Hedge funds take great pains to hide their inner workings. So a recent court case in which Jane Street sued two former employees and Millennium Management, another fund to which they had jumped ship, was immensely pleasing to the firm’s rivals, since it offered a rare view into one of the industry’s giants. Among the revelations: Jane Street’s “most profitable strategy” did not play out on Wall Street, but in the unglamorous Indian options business, where the firm last year earned $1bn.

This news has drawn attention to India’s options market, which is staggeringly large. According to the Futures Industry Association (FIA), a trade body, the country accounted for 84% of all equity option contracts traded globally last year, up from 15% a decade ago. The volume of contracts last year touched 85bn and has more than doubled every year since 2020 (see chart). Most of the frenzy is focused on the National Stock Exchange (NSE), which handles more than 93% of the transactions.