Jane Street barred from Indian markets as regulator freezes $566M

The alternative claim - that large traders do not make decisions based on how their activity will move the market, is of course absurd.

It’s just political. Who is allowed to manipulate and who pays their dues to be able to.

Not really.

In this case it was Millenium ratting out on Jane Street (edit - other way around), but now the entire HFT (Edit: hedge funds. Thanks for the callout avvt4avaw) industry is under extreme scrutiny by SEBI as a result [0]

[0] - https://www.sebi.gov.in/enforcement/orders/jul-2025/interim-...

Yes as presented this behavior is clearly illegal. The next interesting question is if such an obviously illegal strategy was in use by JS, and they also produced the likes of SBF&co, what other related manipulation activity are they partaking in?

This behavior became common in the Indian market after the newer HFTs (Edit: hedge funds. Thanks for the callout avvt4avaw) in the Indian market like Millenium, Jane Street, Citadel, and others setup shop, and explains a LOT of the market weirdness that happened last year. DE Shaw India has been a much smarter player in Indian equities.

Jane Street's kvetching about Millenium showed the spotlight and now everyone will be getting the hammer ("iss hamam mein sabh nange hain"). Jane Street was also dumb enough to do this during the General Election, so now Indian regulators have to do something. This plus the Adani prosecution is a quick win to restore confidence in SEBI.

This is a very weird use of terminology. None of Jane Street, Millennium or Citadel are High Frequency Traders (HFTs). Jane Street is a prop trading firm who engages in market making, but is not primarily known for HFT - they are grey box (i.e. human-in-the-loop) which on the spectrum of market making strategies, is pretty much the opposite end from HFTs. Other firms in this bracket include SIG and DRW.

Millennium and Citadel are both hedge funds, who do not engage in market making at all. They are most similar to other multi-strategy hedge funds like Balyasny or Point72.

You may be thinking of Citadel Securities, who are a market making firm and do engage in high frequency trading. Other large and well known HFT firms include Hudson River Trading, Tower Research, Jump Trading, Virtu, IMC and Optiver.