Whether arbitrage or manipulation, the Jane Street episode highlights a critical truth: markets need more transparency, more accountability, and more human judgment.

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,

The U.S. trading firm’s entities are “further prohibited from buying, selling or otherwise dealing in securities, directly or indirectly.”