This doesn't seem quite as clear-cut as you're making out.

The Securities and Exchange Board of India (SEBI) have accused Jane Street (JS) of market manipulation, JS claims it was legitimate arbitrage, and the case is still ongoing [1].

As I understand it, the ban only applied to Indian securities (not Asian markets as a whole), and was lifted back in July 2025 after JS paid ~$560 million (the alleged ill-gotten gains) into an escrow fund. They don't appear to have resumed trading, though [2].

[1]: https://www.reuters.com/legal/government/us-trading-firm-jan...

[2]: https://www.reuters.com/sustainability/boards-policy-regulat...

Trading the underlying to offset your derivative position isn't fraud.

The above might be too far-fetched as it only applied to India? They did pay a fine to the regulator and resumed trading (might not be the same strategy though)

To OP’s original question, they made $20B last year and have a niche in several financial products

>Janestreet PR team is downvoting. Like always, radio silence and just downvotes.

You're being downvoted for having a needlessly confrontational underinformed hot take on a quant trading firm that is essentially a market maker.