> Jane Street's whole business is front running and arbitrage.

I instinctively hear a reply to this in Jeremy Irons’s voice, “We are selling to willing buyers at the current fair market price”.

I'm sure they make money using HFT strategies but I wouldn't say it's their whole business or even their largest profit center. They put on trades and take on risk in addition to having a market-making business. They're not the reason IEX was formed. Maybe they were a factor but idk.

Man, HN has really started to decline. How exactly is Jane Street front running?

Reacting faster than others to markets is not front running. Seeing someone else's order and putting yours in front of it is front running. Traders on the NYSE Floor would hear a big order is coming in, and put their ticket in front of it- that is front running.

In a computerized world, front running has essentially ceased to exist- the last major enforcement actions I could find are from 2003, when there was still quite a bit of trading done not by pushing buttons on a computer but by making phone calls. Trading on inside information is alive and well, but this is not what JS does at all, that's the realm of hedge funds that have traders that still click on buttons.

I never worked at JS, but have worked in MM.

> HN has really started to decline.

I don't mean to disparage JS and don't necessarily think one way or the other of their actions.

However, you should make yourself aware of their doings in India especially before trashing HN.

https://boringmoney.in/p/jane-street-prefers-arbitrage-manip...

Pay for Order Flow is not literally frontrunning and you can try to justify it as not literally fleecing retail investors but would just be dishonest.

They provide liquidity!