Jane Street suffers $15B hit after meltdown at Situational Awareness • Hacker News Board

Re: Jane Street suffers $15B hit after meltdown at Situational Awareness

#131

Post by f9ad2451 » Sun, Aug 16, 2026, 3:42 PM UTC

alberth wrote: post #77

otterley wrote: post #11

They're still up $25B for the year, so it's hard to feel bad for them :-) On a more serious note, Jane Street has hired some very impressive technical talent. I'd work for them, myself, if I didn't have to relocate to Chicago.

$25B is less than people realize. They have $140B AUM. So they are up ~18%. https://observer.com/2024/11/jane-street-quantitative-tradin...

They're leveraged. $140B in assets is not the same thing as $140B in AUM. The article you posted claims AUM of closer to $27B in 2023; unless you think they made $113B in profit without anyone noticing in 2023, your number is certainly too high. Although, to that point, you're posting a number from 2024 - they've certainly grown since then.

Re: Jane Street suffers $15B hit after meltdown at Situational Awareness

#132

Post by bflesch » Sun, Aug 16, 2026, 5:33 PM UTC

ianm218 wrote: post #66

bflesch wrote: post #56

Earlier quoted context omitted.

Are they "trading" or "high-frequency-ripping-off-retail-investors"? It's easy to make paper billions with synthetic shares and infinite deadline extensions for settlement. I'm old and still remember when Ken Griffin was lauded a clever person before he got caught with his hands in the GME mayo jar..

Isn’t Ken Griffin still considered very clever? Citadel is one of the most successful hedge funds of the is era and has largely accelerated since 2020.

There's this famous line item which is called something like "securities sold but not yet purchased", e.g. with their market maker privilege Citadel can create infinite synthetic shares out of thin air to facilitate that a trade happens, but they have abused this privilege on a very large scale which has created an idiosyncratic risk to all stock market investors.

Due to regulatory capture of the SEC this risk has not materialized in an overall market crash, but they have done numerous accounting shenanigans and deadline extensions to give Citadel more room to breathe.

Re: Jane Street suffers $15B hit after meltdown at Situational Awareness

#133

Post by loeg » Mon, Aug 17, 2026, 12:58 AM UTC

Retric wrote: post #130

loeg wrote: post #129

Earlier quoted context omitted.

> the costs paid by the market is the full operating budget of these companies plus their profits plus their negative externalities Agreed. > which combined ends up being significant No. Combined, it is still de minimis. US equity markets alone trade something like $500B/day of volume or like $125T/year.

> trade something like $500B/day of volume or like $125T/year Trade volume is meaningless in the face of HFT. The very actions you’re defending prove the numbers you just presented have zero relevance and could increase by 100x with zero benefit to anyone. However step back a second. Quoting a number roughly equivalent to global GDP is frankly silly here, but it’s an easy enough mistake to make when your basic premis…

(Trade volume is relevant because it's how market makers make revenue. They make, in aggregate, at most half a penny per share traded.)

Re: Jane Street suffers $15B hit after meltdown at Situational Awareness

#134

Post by Retric » Mon, Aug 17, 2026, 6:07 AM UTC

loeg wrote: post #133

Retric wrote: post #130

Earlier quoted context omitted.

> trade something like $500B/day of volume or like $125T/year Trade volume is meaningless in the face of HFT. The very actions you’re defending prove the numbers you just presented have zero relevance and could increase by 100x with zero benefit to anyone. However step back a second. Quoting a number roughly equivalent to global GDP is frankly silly here, but it’s an easy enough mistake to make when your basic premis…

(Trade volume is relevant because it's how market makers make revenue. They make, in aggregate, at most half a penny per share traded.)

> No. Combined, it is still de minimis. US equity markets alone trade something like $500B/day of volume or like $125T/year.

If that was what you where trying to describe the second sentence is unconnected to the first.

> half a penny per share traded

That’s far from de minimis. Rebalancing a portfolio now becomes quite expensive over a lifetime. You lose 0.5c selling and 0.5c buying, on say a 10$ stock and that’s 0.1% per transaction, and you don’t rebalance once.