A temporary trading ban imposed by India’s securities regulator on Jane Street Group LLC is fueling concerns that volumes in the nation’s bustling derivatives market may drop, hurting business at the top exchange.

Jane Street has been barred from the Indian securities market by its markets regulator, which has said the U.S. firm used its trading strategies to "manipulate" a key stock market index, leading to losses for millions of retail investors,

SEBI has banned the firm from India’s securities markets. The drama has thrown a bright light on Jane Street, a company of legendary opacity even in an industry that prioritises secrecy. And it could carry political and regulatory consequences, not just for Jane Street, but for an entire, ascendant industry of marketmakers.