I was curious what kind of company needed to develop all these different kinds of advanced tech. Turns out it's just so they can be sneaky and trade shares quickly. Kind of sad IMO.
Agreed. Amongst the top 5% smartest quantitatively-minded kids I knew in college, I’d say ~25% of them ended up at quant shops like Jane Street, sometimes straight out of school, sometimes after doing a PhD.
I can only imagine what good that brainpower could do for humanity if it weren’t occupied finding cleverer ways to manipulate electronic money.
Apologies for a (mild) thread-jack. My opinion, one problem with our economic system is focus on short-term results, to the point that several notable companies' stock prices are completely divorced from the reality of their performance. This makes sense if the stock market is primarily a device for gambling or extracting wealth. Investors care less about the prospects of the company than the prospects of the market. I suspect this can trickle all the way down: Board -> CEO -> managers -> individual contributors, all given goals intended to pump the stock short-term, rather than build long-term results.
How do we start to care about quality, building lasting things, fundamentals? What would happen if we taxed capital gains at 100% for the first, I don't know, 3 / 6 / 9 months of holding an asset? Maybe investors would have more incentive to care about fundamentals?
Anyway, I assume I'm wrong about all of this, just looking for someone to explain why. ;-)
Perhaps with the exception of space weapons, none of those would pay Jane Street-tier salaries.
All I'm saying is that I wish our economic system were set up such that people with the mental aptitude to work at a place like Jane Street could earn commensurate salaries for applying that aptitude towards problems with much greater positive externalities than proprietary trading. Alas, it is not so.
It’s incorrect that proprietary trading has negative externalities. It’s also exhausting trying to explain that to an audience that has fundamental misconceptions about economics, financial systems, and monetary systems, so I don’t think I have the energy today. Hopefully someone else will and add to this thread.
I never said it has negative externalities (whether it does or doesn't is a totally separate discussion), only that its positive externalities are certainly much less than some other fields that employ commensurately smart people, e.g. healthcare or climate change research.
But what system should we use that fixes our economic system? This is not so much a defense of capitalism but asking what would be a better replacement. Capitalism in my opinion is the best solution so far that helps drive society forward when society is made up of all types of folks with different opinions and views of the world.
Thing is, there's very few problems that don't involve money or making money that can be solved with software. Even laudable projects like green energy are ultimately capitalist endeavours, since nobody will build solar panels etc for free.
How is it different? We could make an argument that the efficient allocation of capital is what drives the rapid expansion of solar. It provides loans for businesses and individuals, it helps investors raise money, it rewards companies for doing well, it allows farmers to hedge crops. It is not perfect but it helps facilitate most of our modern society. Not perfect but which system would be better?
If you could either improve hft by some percentage, which slightly increases market liquidity and has downstream impacts, or you could work on making the manufacturing cost of solar panels the same percentage cheaper or making then some percentage more efficient, the latter option is more direct.
I think it would be good if our best minds went to work on directly creating better things instead of indirectly moving money around efficiently so that other people might eventually find success.
I get the intuition, making solar panels cheaper feels more “direct” than making markets more liquid. But that framing underestimates how much “indirect” efficiency matters.
Capital has to get from savers to builders. Liquidity, tighter spreads, and efficient pricing lower the cost of capital for all projects, including the ones building better solar panels. If financing those projects is cheaper and faster because markets function well, more of them get done.
It’s easy to glorify the visible widget (solar panels) and discount the invisible infrastructure (capital markets), but the latter is what makes scaling the former possible. The system needs both.
There is a difference between 1) doing something valuable that is then rewarded with money through market mechanics and 2) maximizing money as an end in itself. The former is a great feature of capitalism, the latter is its tragedy and Achilles heel.
In the first case, money is important (if you completely ignore it, you can’t deliver value sustainably), but in a perfect world it should be more like fuel and an indicator that you are doing something right.
Already said it before but the efficient allocation of capital benefits all of us. From the farmer hedging their crop prices to the local manufacturing company that is drawing a loan to expand their business. What system would you have in its place?
Off the top of my head, for the manufacturing company, why not have people invest in it? If it is doing something good, people will buy shares, and the company will gain the money to expand. For the farmer, if the issue is harvest instability, why not amortise the cost accordingly?
That sounds tidy in theory, but in practice it’s rarely that simple. Investors don’t just fund “good” companies, they fund opportunities with risk/return profiles that make sense relative to alternatives. Plenty of companies doing socially useful things struggle to raise capital because the payoff is long, messy, or uncertain.
Same with farming. “Amortize the cost” only works if margins and credit markets allow it. A small farmer facing price volatility, weather risk, and thin margins doesn’t have the same access to capital markets as a Fortune 500 manufacturer.
The whole point of efficient markets is to reduce those frictions, to better allocate risk and capital so that good projects (whether in manufacturing or farming) don’t just work “in theory.”
For me, no better system exists in the world. It’s not perfect but until there is something that works better I will have the agree with it.
Exactly what I am lamenting in my original comment. Investors chase returns, i.e. money for its sake.
As long as that is conceptually a thing, it is a no-brainer to fund a bad company if you are sure its shares will go up in price during the term of your investment; it is also in your interest (and acceptable within the “money for its own sake” framework) to ensure its shares do go up by helping hype it up; etc.
This all, I believe, is a source of strong and far-reaching negative externalities, which I am far from sure are trumped by its potential benefits.
> A small farmer facing price volatility, weather risk, and thin margins doesn’t have the same access to capital
Why do you need access to capital in order to price in the risks or the cost of relevant insurance? (That’s what I meant by amortising, I might have used a wrong term.)
Why are you “facing thin margins” like it is not an open market where you set your prices and your margin is your choice?
Basically, SEBI investigated Jane Street's trading on January 17, 2024, when the firm allegedly made about $86 million in a single day through what regulators term "intra-day index manipulation."
HFT and Ads are two places which (currently) print money, so it vacuums up all the talent, and puts it to use growing their already-huge revenue streams.
Can someone who actually understands the topic explain to me (or link good resources) why/if what they do is useful to anyone?
Or are they literally just in the business of making money?
(anyone except themselves of course. I'm serious, any hints of irony are unintended)
It's a common rhetoric from someone who has no clue about financial markets (the person you replied to).
Suppose you want to invest in S&p500 so you want to buy the ETF. Someone like Jane Street can create sell you this ETF, and take care of the risk that comes along with it. For example, the price they sell you this ETF should take into account the pricing of underlying stocks. While it sounds trivial, doing this profitably (and therefore sustainably) is a tough job. And doing it competitively to offer you a good price on it is an even tougher job.
Is that why they got banned in India recently? Because they were too good at offering complex financial instruments to customers at competitive prices?
Ultimately companies like Jane Street have no moral rudder and it is a waste of talent for smart young people to work for them, but we are so far beyond such considerations at this point that it sounds naive to even suggest that maybe talented people should work on things that make society better for everyone and care about the moral implications of their work. Instead everyone is looking for a way to contribute to the coming dystopia in whatever way they can because that's where the money is.
At the end of the day they are a prop firm. They are a business trying to make money and part of that is market making but it’s not solely market making.
You may not like it but we function in a capitalist society and as such the efficiency of markets is part of that. To have that happen usually requires the market as a whole participating and that includes firms like Jane Street. In the India case I don’t know if what they were doing was illegal or not, India is complicated and the laws there in my opinion are influenced not as much by standards but how well you scratch the itch of others. It is clear the option markets in India was/is highly inefficient in that Jane Street was able to pull the rug over and over. I would be curious who the counter parties were and if this is more about pride of Indian financial institutions not being competent instead of this being illegal. Thinking more about Hindenburg and how India reacted. In the US it feels like a gray area because at the end of the day the options market was clearly clueless on how they should be pricing the options.
Speaking from a US perspective people get thorny on these topics but I think it’s great that folks are always pushing the boundaries. This type of law is tested and we figure out what is ok and what is not. It’s often not cut and dry. Maybe Jane Street was entirely in the wrong in India and they will pay a price. Maybe not. Hopefully their markets learn and benefit from it.
I don’t believe any of us are in a position to say how folks should be spending their time. If we went down that road we could probably argue it back to nobody should be working and should simply be farming for our own food.
The majority of counterparties were regular citizens, who did not understand that what Jane Street was doing was even possible.
Money is debt, you can’t make it without someone else owing it. Taking billions in profits from India’s stock market is pretty straightforward, millions of Indians lost their savings.
You’re not entirely wrong. India does have a problem with gambling and especially in Bank Nifty. I think something like 50% of options volume is retail, which is wildly high. Just because there is a gambling problem does not make it “pretty straightforward”. The courts will hopefully figure it out to their local pleasing.
Edit: I don’t think my point was clear. If you are going to allow retail in the options market, you should also be ok with sophisticated actors participating in it.
It would be nice if smart people would not require law to operate in an ethical way. For complicated problems, and for people who are just plain stupid, it's nice to have law and law enforcement, so that capitalist society can work properly.
But the idea that smart people should "push the boundaries" to find out "what is ok and what is not" is either naive or borderline sociopathic IMNSHO.
I’m not being naive or sociopathic here, I’m pointing out how securities law actually functions, at least in the U.S. It’s rarely as cut-and-dry as you suggest. The courts exist precisely to resolve ambiguity, and there’s always some ebb and flow depending on the administration and the legal environment.
Before throwing around labels like “naive” or “sociopath,” it’s worth recognizing that a capitalist system relies on efficient markets, and efficient markets depend on laws being tested and clarified through the courts. That process benefits everyone.
I’m not making an ethical defense of any specific behavior. I’m saying that just because someone benefits from mispricing in a market doesn’t automatically make it unethical. The courts help define those boundaries. If you reject that premise and prefer a system without capitalism, then we’re simply talking past each other.
And for what it’s worth, tossing out loaded terms like “naive” or “sociopath” isn’t exactly an argument, it’s just lazy rhetoric. It’s ok for us to disagree but why use such a lazy argument?
I'm not opposed to capitalism, and enjoy its benefits everyday. I don 't however agree that efficient markets are required for capitalism. I also don't think that HFT is the only way to create efficient markets.
I do however believe that gaming the system for personal profit is unethical. The intention of the law might have been to build a playground for people to enrich themselves, but from a Christian standpoint, I don 't think this always works out well for society. I'm not a Christian, but I do like some of its values.
I was a bit disappointed about the suggestion that capitalism requires certain things that make Jane Street a necessity. This is not a fact, nor does the current process benefit everyone equally. Rejecting that notion, and possibly reading a bit too much into that, is what caused me to use said terms.
I do agree that we are probably talking past each other though :)
> I don’t believe any of us are in a position to say how folks should be spending their time.
We obviously can't tell people how to spend their time, but we can point out that there might be moral reasons to avoid working in industries and for companies with particularly strong negative impacts on society.
> If we went down that road we could probably argue it back to nobody should be working and should simply be farming for our own food.
This is a classic false dichotomy. There are an infinite number of middle grounds between farming for our own food and an ultracapitalist dystopia in which morality is replaced by profit.
Sure, but that’s kind of my point, once you open the door to moral gatekeeping of jobs, it gets very slippery very fast. You can always trace the “negative impact” argument up or down the stack. That accounting software? It helps a business capture margin. That business? Probably acting as a middleman extracting value from someone else. Even compiler contributions ultimately fuel businesses optimizing for profit.
You’re right that there are middle grounds between subsistence farming and some caricature of ultracapitalism, but deciding where to draw that line in practice is messy. Pretending it’s obvious which industries are “moral” and which aren’t usually says more about someone’s priors than it does about some universal ethical framework.
At the end of the day, efficient allocation of capital, imperfect as it is, is what makes the system work. It drives productivity gains, lowers costs, and ultimately raises living standards across the board.
> It's a common rhetoric from someone who has no clue about financial markets (the person you replied to).
I think what OP meant is that producing all this fancy advanced tech just to play the financial game isn't all that much benefit for society.
And when looking at societal development in the last couple of decades with the increasing gap in distribution of wealth, social mobility and overall life expectancy declining and other such metrics, I think it's a valid standpoint that maybe, the collective smarts of our society could be allocated a bit better than putting them into companies like Jane Street; as impressive as their work is.
That is true but capitalism sadly encourages the more profit the better. With making less and less in traditional research jobs for example and rising costs, this positions come more attractive by the second. It is sad to see.
> Or are they literally just in the business of making money?
All for-profit businesses can be viewed abstractly as “in the business of making money”, so this doesn’t really distinguish Jane Street in any way.
> … why/if what they do is useful to anyone?
The utility that Jane Street provides is to the be a persistent buyer and seller of equities. Basically you can call them at any time and buy shares or sell shares. Most shareholders do not trade very often so without a “market maker” like Jane Street it can be a lot of work finding a buyer/seller who is willing to trade on your schedule at the current market price. You’ll have to pay them extra to convince them to trade, which makes it harder to trade profitably. Jane Street significantly lowers the price and makes trading easier (“provides liquidity to the market”).
I do like this take and one of the reasons I don’t like how many folks pile in on the same theme “these folks are wasting their lives”. We could make the same reductionist conclusion for probably most of the people here on HN.
Both ad tech and quant work are essentially involuted in that you're spending ever greater amounts of effort and manpower to squeeze out marginal gains because of how much profit doing so provides. Society would not significantly notice or suffer if we spent half as much time on things like this. There are much bigger things we need to do.
the premise here is that market makers and arbitrageurs are crucial for efficiently allocating capital. enabling sellers to sell to the highest bidder and buyers to buy from the cheapest vendor means less capital wasted(?)
in my experience Jane Street make no attempt to defend the financial system; such societal benefits are obvious or implicit.
whether you (or they!) really buy that is irrelevant
HFT is a different thing from what is being discussed in this thread. With HFT you're talking custom ASICs running within light-nanoseconds range of the target exchange. Ocaml very much isn't in this picture. This is about human-speed trading. Which also provides liquidity and correction of instrument prices towards their fair value, just at a different level.
The societal value of either is debatable all the same, mind you. It's more that wherever you have markets, you have money-making opportunities that can be leveraged, and therefore are.
Market makers or other similar HFT are providing liquidity in an efficient manner to the markets. The benefit is often debated but for the majority of retail and institutional investors, spreads have never been lower. Instead of a guy at the floor swallowing large margins up, you have bots electronically vacuuming pennies.
Of course the whole point for a firm like Jane Street is to make money. To make money means they are competing with someone and that someone could be a loser depending on the scenario.
My own opinion, most folks don’t like market makers or folks who work in financial markets are simply not well informed. The efficient allocation of capital is a valuable service to humans in a capitalist society. People often forget how wide spreads were in the past and that humans were swallowing that margin up with little competition. Now market making is highly competitive and because of it investors both small and large benefit from it.
The societal value of liquidity and a narrower bid/ask spread, while non-zero, is not even remotely commensurate with the bucketloads of cash that the top firms bring in.
It's mercenary work, plain and simple. Advanced, interesting, full of juicy maths, highly competitive, rewarding, but mercenary. No one's doing this job for the good of the world, come on.
Give some of your earnings to trans defense NGOs, now that makes a difference and I'll be personally grateful.
I used to work there, so with the appropriate deference to that Upton Sinclair quote about paychecks:
Market makers like JS vastly increase market liquidity across all sectors, which is required for modern high-efficiency economies to work. McDonalds prices are possible because there's enough liquidity in corn futures.
More abstractly, high market liquidity corresponds to higher-confidence information about the future, which hedge funds generate (and distribute for a low fee via markets), allowing for more impressive planning ahead.
Also, you know how when you buy stocks it doesn't cost you anything and you often get better-than-public-book execution prices? That didn't happen prior to modern electronic market makers. Multiply that efficiency gain by umpteen trades every day.
In general, "being in the business of making money" inherently requires you to do something useful to get paid, to the extent you're not just abusing a principle agent problem or something. The most credible argument for hedge funds making money without doing something useful is that they're doing cantillon effect harvesting or something. I think that's pretty small overall.
HFTs competing with each other at market making lower spreads; the cost retailers/institutions need to pay to enter a position. Prior to algorithmic trading, you might need to pay a whole percentage point or more (100 basis points), now spreads on the most popular products are so tightly quoted that it can cost less than 1 basis point (0.01%) to enter a position.
Companies like JaneStreet, 2Sigma, etc employ some of the best software engineers, mathematicians, physicists and what not just so they can
- have better weather forecasts to identify whether a 1 degree delta in South CA can increase oil costs cents on the barrel,
- run pandemic simulations to identify how the spread might happen and where inflation will rise so they move faster,
- track occupancy rates for pharmacies, hotels, casinos, etc via satellite imaging to identify spikes in usage,
- track the tiniest of things like butterfly populations to identify increase in earnings for certain brands of hotels,
- build some of the most efficient software and write their own compilers
all so that they can move money around [and do so quickly].
Finance is not alone either. A non-trivial amount of big tech is on tracking users and serving ads better.
Do I blame the engineers? No.
I am just lamenting the state of society since this is how we have the brightest among us function and work.
I can construct even more compelling arguments for the uselessness or active harmfulness of most tech jobs.
The only "actually useful" tech jobs if we're going to consistently apply a bar that excludes finance would be stuff like aerospace R&D or ERM systems. Which, to be clear, I would love if society incentivized more strongly. But finance is hardly the worst offender here.
But plenty of people here do work on real products. Planes need software, browsers need security patches, hell even your accounting app is good value over the days of doing that all by hand.
Fair, but let’s be honest: even in your accounting app example, the “value” is ultimately in helping a business capture margin more efficiently. That business, in turn, is usually extracting value as a middleman somewhere else in the chain. Same with ad tech, finance, or even a lot of enterprise software, you’re greasing the gears of profit capture, not curing cancer.
That’s not a moral indictment, just a reminder that most of our jobs (mine included) exist to make capital move faster or stickier. Calling one sector “real products” and another “not benefiting society” is a bit of a convenient fiction.
I can't say that about my job; I am providing tools for engineers to use and making things better. As part of my job I am expected to contribute to CPython, and rustc among other things.
That’s great work, but even there you’re mostly building tools that make other engineers more efficient at building more tools. It’s not that the work lacks value it absolutely does, but it’s still part of the same recursive loop where the ultimate “benefit to society” gets pretty abstract. At the end of the chain, most of those tools are still helping businesses optimize, capture margin, or intermediate in some way.
It’s fine to take pride in craftsmanship, just maybe less fine to pretend it’s immune from the same critique applied elsewhere.
Plenty people of here work doing basically the same to maximize the amount of time people, including children and teens, spend staring at rectangular lights to show them ads.
Some amount of extremely competent engineers worked on the tech that made it possible to target beauty ads to insecure teen girls when they deleted a selfie.
Some amount of extremely competent engineers where complicit in building the tech that stoked the fire under the Rohingya genocide.
The thing I’m most impressed by is that I didn’t see a single LLM wrapper project. In fact I didn’t see a single project that directly involved an LLM at all.
I've not heard of Jane Street, but looking at the site, it seems they're quite the tech-savvy group for an _asset trading_ company. And reading the article, they apparently "trade" (pun intended) in quite a few different things from CSS to OCaml, which is really nice to see for a place that doesn't directly deal with software as their [business] product (or did I misunderstand their market?).
They are basically the main company driving OCaml development outside INRIA, and the main authors behind Real World Ocaml book (https://dev.realworldocaml.org), which followed up a similar one for Haskell.
1. Watch Stand-Up Maths and Numberphile videos on YouTube and do not skip the sponsor advertisement readings, e.g. https://youtube.com/watch?v=eqyuQZHfNPQ .
Jane Street is a technology company first and foremost whose main product is high frequency training, which is similar to mang of these neo-hedge funds (e.g. HRT, Citadel). Which is contrasted to the more established asset managers (e.g. BlackRock, Vanguard, BRK, etc) which I can say from experience are corps tied down in bureaucracy.
> which is really nice to see for a place that doesn't directly deal with software as their [business] product
Part of Jane Street's business is HFT, and software is the "product" of HFT firms, because without extremely low-latency software (and hardware) they cannot make money.
My interns always got very speculative projects, the kind that were low probability of working out so didnt want to waste (more valuable) time exploring. If they ever found anything useful it was 100% reworked from scratch.
My preference was for both sides to learn at the end of the day.
One of my favorite experiences was that as an intern I shipped what I thought was a useful tool. When I came back full time a year later it had spread and was pretty popular among a subset of the company!
I was curious what kind of company needed to develop all these different kinds of advanced tech. Turns out it's just so they can be sneaky and trade shares quickly. Kind of sad IMO.
Agreed. Amongst the top 5% smartest quantitatively-minded kids I knew in college, I’d say ~25% of them ended up at quant shops like Jane Street, sometimes straight out of school, sometimes after doing a PhD.
I can only imagine what good that brainpower could do for humanity if it weren’t occupied finding cleverer ways to manipulate electronic money.
Apologies for a (mild) thread-jack. My opinion, one problem with our economic system is focus on short-term results, to the point that several notable companies' stock prices are completely divorced from the reality of their performance. This makes sense if the stock market is primarily a device for gambling or extracting wealth. Investors care less about the prospects of the company than the prospects of the market. I suspect this can trickle all the way down: Board -> CEO -> managers -> individual contributors, all given goals intended to pump the stock short-term, rather than build long-term results.
How do we start to care about quality, building lasting things, fundamentals? What would happen if we taxed capital gains at 100% for the first, I don't know, 3 / 6 / 9 months of holding an asset? Maybe investors would have more incentive to care about fundamentals?
Anyway, I assume I'm wrong about all of this, just looking for someone to explain why. ;-)
They could spend their time playing chess, solving Fermat's last theorem, or invent space weapons. And why stop at humanity?
Perhaps with the exception of space weapons, none of those would pay Jane Street-tier salaries.
All I'm saying is that I wish our economic system were set up such that people with the mental aptitude to work at a place like Jane Street could earn commensurate salaries for applying that aptitude towards problems with much greater positive externalities than proprietary trading. Alas, it is not so.
It’s incorrect that proprietary trading has negative externalities. It’s also exhausting trying to explain that to an audience that has fundamental misconceptions about economics, financial systems, and monetary systems, so I don’t think I have the energy today. Hopefully someone else will and add to this thread.
I never said it has negative externalities (whether it does or doesn't is a totally separate discussion), only that its positive externalities are certainly much less than some other fields that employ commensurately smart people, e.g. healthcare or climate change research.
> I can only imagine what good that brainpower could do for humanity if it weren’t occupied finding cleverer ways to manipulate electronic money.
Maybe humanity can start paying them decent money first?
You're right, we should fix our economic system so that it better incentivizes things we care about rather than stuff like quant research.
But what system should we use that fixes our economic system? This is not so much a defense of capitalism but asking what would be a better replacement. Capitalism in my opinion is the best solution so far that helps drive society forward when society is made up of all types of folks with different opinions and views of the world.
Why did you say we, when you meant I?
Thing is, there's very few problems that don't involve money or making money that can be solved with software. Even laudable projects like green energy are ultimately capitalist endeavours, since nobody will build solar panels etc for free.
Yeah but building stuff to sell is fairly different from making trades faster or other market stuff?
It's another level detached from real value
How is it different? We could make an argument that the efficient allocation of capital is what drives the rapid expansion of solar. It provides loans for businesses and individuals, it helps investors raise money, it rewards companies for doing well, it allows farmers to hedge crops. It is not perfect but it helps facilitate most of our modern society. Not perfect but which system would be better?
If you could either improve hft by some percentage, which slightly increases market liquidity and has downstream impacts, or you could work on making the manufacturing cost of solar panels the same percentage cheaper or making then some percentage more efficient, the latter option is more direct.
I think it would be good if our best minds went to work on directly creating better things instead of indirectly moving money around efficiently so that other people might eventually find success.
I get the intuition, making solar panels cheaper feels more “direct” than making markets more liquid. But that framing underestimates how much “indirect” efficiency matters.
Capital has to get from savers to builders. Liquidity, tighter spreads, and efficient pricing lower the cost of capital for all projects, including the ones building better solar panels. If financing those projects is cheaper and faster because markets function well, more of them get done.
It’s easy to glorify the visible widget (solar panels) and discount the invisible infrastructure (capital markets), but the latter is what makes scaling the former possible. The system needs both.
There is a difference between 1) doing something valuable that is then rewarded with money through market mechanics and 2) maximizing money as an end in itself. The former is a great feature of capitalism, the latter is its tragedy and Achilles heel.
In the first case, money is important (if you completely ignore it, you can’t deliver value sustainably), but in a perfect world it should be more like fuel and an indicator that you are doing something right.
Already said it before but the efficient allocation of capital benefits all of us. From the farmer hedging their crop prices to the local manufacturing company that is drawing a loan to expand their business. What system would you have in its place?
Off the top of my head, for the manufacturing company, why not have people invest in it? If it is doing something good, people will buy shares, and the company will gain the money to expand. For the farmer, if the issue is harvest instability, why not amortise the cost accordingly?
That sounds tidy in theory, but in practice it’s rarely that simple. Investors don’t just fund “good” companies, they fund opportunities with risk/return profiles that make sense relative to alternatives. Plenty of companies doing socially useful things struggle to raise capital because the payoff is long, messy, or uncertain.
Same with farming. “Amortize the cost” only works if margins and credit markets allow it. A small farmer facing price volatility, weather risk, and thin margins doesn’t have the same access to capital markets as a Fortune 500 manufacturer.
The whole point of efficient markets is to reduce those frictions, to better allocate risk and capital so that good projects (whether in manufacturing or farming) don’t just work “in theory.”
For me, no better system exists in the world. It’s not perfect but until there is something that works better I will have the agree with it.
> Investors don’t just fund “good” companies
Exactly what I am lamenting in my original comment. Investors chase returns, i.e. money for its sake.
As long as that is conceptually a thing, it is a no-brainer to fund a bad company if you are sure its shares will go up in price during the term of your investment; it is also in your interest (and acceptable within the “money for its own sake” framework) to ensure its shares do go up by helping hype it up; etc.
This all, I believe, is a source of strong and far-reaching negative externalities, which I am far from sure are trumped by its potential benefits.
> A small farmer facing price volatility, weather risk, and thin margins doesn’t have the same access to capital
Why do you need access to capital in order to price in the risks or the cost of relevant insurance? (That’s what I meant by amortising, I might have used a wrong term.)
Why are you “facing thin margins” like it is not an open market where you set your prices and your margin is your choice?
Jane Street is in hot water in India:
https://www.bbc.com/news/articles/c5y0zgrevl1o
Basically, SEBI investigated Jane Street's trading on January 17, 2024, when the firm allegedly made about $86 million in a single day through what regulators term "intra-day index manipulation."
HFT and Ads are two places which (currently) print money, so it vacuums up all the talent, and puts it to use growing their already-huge revenue streams.
Can someone who actually understands the topic explain to me (or link good resources) why/if what they do is useful to anyone? Or are they literally just in the business of making money? (anyone except themselves of course. I'm serious, any hints of irony are unintended)
It's a common rhetoric from someone who has no clue about financial markets (the person you replied to).
Suppose you want to invest in S&p500 so you want to buy the ETF. Someone like Jane Street can create sell you this ETF, and take care of the risk that comes along with it. For example, the price they sell you this ETF should take into account the pricing of underlying stocks. While it sounds trivial, doing this profitably (and therefore sustainably) is a tough job. And doing it competitively to offer you a good price on it is an even tougher job.
Is that why they got banned in India recently? Because they were too good at offering complex financial instruments to customers at competitive prices?
Ultimately companies like Jane Street have no moral rudder and it is a waste of talent for smart young people to work for them, but we are so far beyond such considerations at this point that it sounds naive to even suggest that maybe talented people should work on things that make society better for everyone and care about the moral implications of their work. Instead everyone is looking for a way to contribute to the coming dystopia in whatever way they can because that's where the money is.
They got banned because they were accused of pretty bad market manipulation (which Jane Street denies of course)
At the end of the day they are a prop firm. They are a business trying to make money and part of that is market making but it’s not solely market making.
You may not like it but we function in a capitalist society and as such the efficiency of markets is part of that. To have that happen usually requires the market as a whole participating and that includes firms like Jane Street. In the India case I don’t know if what they were doing was illegal or not, India is complicated and the laws there in my opinion are influenced not as much by standards but how well you scratch the itch of others. It is clear the option markets in India was/is highly inefficient in that Jane Street was able to pull the rug over and over. I would be curious who the counter parties were and if this is more about pride of Indian financial institutions not being competent instead of this being illegal. Thinking more about Hindenburg and how India reacted. In the US it feels like a gray area because at the end of the day the options market was clearly clueless on how they should be pricing the options.
Speaking from a US perspective people get thorny on these topics but I think it’s great that folks are always pushing the boundaries. This type of law is tested and we figure out what is ok and what is not. It’s often not cut and dry. Maybe Jane Street was entirely in the wrong in India and they will pay a price. Maybe not. Hopefully their markets learn and benefit from it.
I don’t believe any of us are in a position to say how folks should be spending their time. If we went down that road we could probably argue it back to nobody should be working and should simply be farming for our own food.
The majority of counterparties were regular citizens, who did not understand that what Jane Street was doing was even possible.
Money is debt, you can’t make it without someone else owing it. Taking billions in profits from India’s stock market is pretty straightforward, millions of Indians lost their savings.
You’re not entirely wrong. India does have a problem with gambling and especially in Bank Nifty. I think something like 50% of options volume is retail, which is wildly high. Just because there is a gambling problem does not make it “pretty straightforward”. The courts will hopefully figure it out to their local pleasing.
Edit: I don’t think my point was clear. If you are going to allow retail in the options market, you should also be ok with sophisticated actors participating in it.
It would be nice if smart people would not require law to operate in an ethical way. For complicated problems, and for people who are just plain stupid, it's nice to have law and law enforcement, so that capitalist society can work properly.
But the idea that smart people should "push the boundaries" to find out "what is ok and what is not" is either naive or borderline sociopathic IMNSHO.
I’m not being naive or sociopathic here, I’m pointing out how securities law actually functions, at least in the U.S. It’s rarely as cut-and-dry as you suggest. The courts exist precisely to resolve ambiguity, and there’s always some ebb and flow depending on the administration and the legal environment.
Before throwing around labels like “naive” or “sociopath,” it’s worth recognizing that a capitalist system relies on efficient markets, and efficient markets depend on laws being tested and clarified through the courts. That process benefits everyone.
I’m not making an ethical defense of any specific behavior. I’m saying that just because someone benefits from mispricing in a market doesn’t automatically make it unethical. The courts help define those boundaries. If you reject that premise and prefer a system without capitalism, then we’re simply talking past each other.
And for what it’s worth, tossing out loaded terms like “naive” or “sociopath” isn’t exactly an argument, it’s just lazy rhetoric. It’s ok for us to disagree but why use such a lazy argument?
I'm not opposed to capitalism, and enjoy its benefits everyday. I don 't however agree that efficient markets are required for capitalism. I also don't think that HFT is the only way to create efficient markets.
I do however believe that gaming the system for personal profit is unethical. The intention of the law might have been to build a playground for people to enrich themselves, but from a Christian standpoint, I don 't think this always works out well for society. I'm not a Christian, but I do like some of its values.
I was a bit disappointed about the suggestion that capitalism requires certain things that make Jane Street a necessity. This is not a fact, nor does the current process benefit everyone equally. Rejecting that notion, and possibly reading a bit too much into that, is what caused me to use said terms.
I do agree that we are probably talking past each other though :)
> I don’t believe any of us are in a position to say how folks should be spending their time.
We obviously can't tell people how to spend their time, but we can point out that there might be moral reasons to avoid working in industries and for companies with particularly strong negative impacts on society.
> If we went down that road we could probably argue it back to nobody should be working and should simply be farming for our own food.
This is a classic false dichotomy. There are an infinite number of middle grounds between farming for our own food and an ultracapitalist dystopia in which morality is replaced by profit.
Sure, but that’s kind of my point, once you open the door to moral gatekeeping of jobs, it gets very slippery very fast. You can always trace the “negative impact” argument up or down the stack. That accounting software? It helps a business capture margin. That business? Probably acting as a middleman extracting value from someone else. Even compiler contributions ultimately fuel businesses optimizing for profit.
You’re right that there are middle grounds between subsistence farming and some caricature of ultracapitalism, but deciding where to draw that line in practice is messy. Pretending it’s obvious which industries are “moral” and which aren’t usually says more about someone’s priors than it does about some universal ethical framework.
At the end of the day, efficient allocation of capital, imperfect as it is, is what makes the system work. It drives productivity gains, lowers costs, and ultimately raises living standards across the board.
Most likely they got slapped in india because a domestic market maker bribed the right regulators and JS did not
> It's a common rhetoric from someone who has no clue about financial markets (the person you replied to).
I think what OP meant is that producing all this fancy advanced tech just to play the financial game isn't all that much benefit for society.
And when looking at societal development in the last couple of decades with the increasing gap in distribution of wealth, social mobility and overall life expectancy declining and other such metrics, I think it's a valid standpoint that maybe, the collective smarts of our society could be allocated a bit better than putting them into companies like Jane Street; as impressive as their work is.
That is true but capitalism sadly encourages the more profit the better. With making less and less in traditional research jobs for example and rising costs, this positions come more attractive by the second. It is sad to see.
> Or are they literally just in the business of making money?
All for-profit businesses can be viewed abstractly as “in the business of making money”, so this doesn’t really distinguish Jane Street in any way.
> … why/if what they do is useful to anyone?
The utility that Jane Street provides is to the be a persistent buyer and seller of equities. Basically you can call them at any time and buy shares or sell shares. Most shareholders do not trade very often so without a “market maker” like Jane Street it can be a lot of work finding a buyer/seller who is willing to trade on your schedule at the current market price. You’ll have to pay them extra to convince them to trade, which makes it harder to trade profitably. Jane Street significantly lowers the price and makes trading easier (“provides liquidity to the market”).
I do like this take and one of the reasons I don’t like how many folks pile in on the same theme “these folks are wasting their lives”. We could make the same reductionist conclusion for probably most of the people here on HN.
Both ad tech and quant work are essentially involuted in that you're spending ever greater amounts of effort and manpower to squeeze out marginal gains because of how much profit doing so provides. Society would not significantly notice or suffer if we spent half as much time on things like this. There are much bigger things we need to do.
the premise here is that market makers and arbitrageurs are crucial for efficiently allocating capital. enabling sellers to sell to the highest bidder and buyers to buy from the cheapest vendor means less capital wasted(?)
in my experience Jane Street make no attempt to defend the financial system; such societal benefits are obvious or implicit.
whether you (or they!) really buy that is irrelevant
AFAIU the service HFT forms provide to the market is liquidity. Basically allowing you to sell stocks/options as soon as you feel like it.
In turn that leads to more efficient markets since prices converge to their "correct" value faster.
HFT is a different thing from what is being discussed in this thread. With HFT you're talking custom ASICs running within light-nanoseconds range of the target exchange. Ocaml very much isn't in this picture. This is about human-speed trading. Which also provides liquidity and correction of instrument prices towards their fair value, just at a different level.
The societal value of either is debatable all the same, mind you. It's more that wherever you have markets, you have money-making opportunities that can be leveraged, and therefore are.
Market makers or other similar HFT are providing liquidity in an efficient manner to the markets. The benefit is often debated but for the majority of retail and institutional investors, spreads have never been lower. Instead of a guy at the floor swallowing large margins up, you have bots electronically vacuuming pennies.
Of course the whole point for a firm like Jane Street is to make money. To make money means they are competing with someone and that someone could be a loser depending on the scenario.
My own opinion, most folks don’t like market makers or folks who work in financial markets are simply not well informed. The efficient allocation of capital is a valuable service to humans in a capitalist society. People often forget how wide spreads were in the past and that humans were swallowing that margin up with little competition. Now market making is highly competitive and because of it investors both small and large benefit from it.
The societal value of liquidity and a narrower bid/ask spread, while non-zero, is not even remotely commensurate with the bucketloads of cash that the top firms bring in.
It's mercenary work, plain and simple. Advanced, interesting, full of juicy maths, highly competitive, rewarding, but mercenary. No one's doing this job for the good of the world, come on.
Give some of your earnings to trans defense NGOs, now that makes a difference and I'll be personally grateful.
I used to work there, so with the appropriate deference to that Upton Sinclair quote about paychecks:
Market makers like JS vastly increase market liquidity across all sectors, which is required for modern high-efficiency economies to work. McDonalds prices are possible because there's enough liquidity in corn futures.
More abstractly, high market liquidity corresponds to higher-confidence information about the future, which hedge funds generate (and distribute for a low fee via markets), allowing for more impressive planning ahead.
Also, you know how when you buy stocks it doesn't cost you anything and you often get better-than-public-book execution prices? That didn't happen prior to modern electronic market makers. Multiply that efficiency gain by umpteen trades every day.
In general, "being in the business of making money" inherently requires you to do something useful to get paid, to the extent you're not just abusing a principle agent problem or something. The most credible argument for hedge funds making money without doing something useful is that they're doing cantillon effect harvesting or something. I think that's pretty small overall.
HFTs competing with each other at market making lower spreads; the cost retailers/institutions need to pay to enter a position. Prior to algorithmic trading, you might need to pay a whole percentage point or more (100 basis points), now spreads on the most popular products are so tightly quoted that it can cost less than 1 basis point (0.01%) to enter a position.
What use was it to anyone when Gerolamo Cardano devised the rules of probability in order to win at gambling?
Reality is far more sad.
Companies like JaneStreet, 2Sigma, etc employ some of the best software engineers, mathematicians, physicists and what not just so they can
all so that they can move money around [and do so quickly].Finance is not alone either. A non-trivial amount of big tech is on tracking users and serving ads better.
Do I blame the engineers? No.
I am just lamenting the state of society since this is how we have the brightest among us function and work.
I can construct even more compelling arguments for the uselessness or active harmfulness of most tech jobs.
The only "actually useful" tech jobs if we're going to consistently apply a bar that excludes finance would be stuff like aerospace R&D or ERM systems. Which, to be clear, I would love if society incentivized more strongly. But finance is hardly the worst offender here.
Could we not make the same statement for most of the jobs people work here on HN?
Anyone who works in ad tech, sure.
But plenty of people here do work on real products. Planes need software, browsers need security patches, hell even your accounting app is good value over the days of doing that all by hand.
Fair, but let’s be honest: even in your accounting app example, the “value” is ultimately in helping a business capture margin more efficiently. That business, in turn, is usually extracting value as a middleman somewhere else in the chain. Same with ad tech, finance, or even a lot of enterprise software, you’re greasing the gears of profit capture, not curing cancer.
That’s not a moral indictment, just a reminder that most of our jobs (mine included) exist to make capital move faster or stickier. Calling one sector “real products” and another “not benefiting society” is a bit of a convenient fiction.
I can't say that about my job; I am providing tools for engineers to use and making things better. As part of my job I am expected to contribute to CPython, and rustc among other things.
That’s great work, but even there you’re mostly building tools that make other engineers more efficient at building more tools. It’s not that the work lacks value it absolutely does, but it’s still part of the same recursive loop where the ultimate “benefit to society” gets pretty abstract. At the end of the chain, most of those tools are still helping businesses optimize, capture margin, or intermediate in some way.
It’s fine to take pride in craftsmanship, just maybe less fine to pretend it’s immune from the same critique applied elsewhere.
Exercise for the reader; stay a while, and listen.
Once you start noticing things changing, try to identify how you could profit off of it. If it's a change, then there's profit to be made somehow.
Any anecdote is a potential lead.
Plenty people of here work doing basically the same to maximize the amount of time people, including children and teens, spend staring at rectangular lights to show them ads.
Some amount of extremely competent engineers worked on the tech that made it possible to target beauty ads to insecure teen girls when they deleted a selfie.
Some amount of extremely competent engineers where complicit in building the tech that stoked the fire under the Rohingya genocide.
I could go on, but I think you get the point.
People in glass houses shouldnt throw stones. Tech is more parastic.
While a little harsh I don’t entirely disagree. Depending on your lens, very few of us here on HN are doing something valuable for society.
The thing I’m most impressed by is that I didn’t see a single LLM wrapper project. In fact I didn’t see a single project that directly involved an LLM at all.
I've not heard of Jane Street, but looking at the site, it seems they're quite the tech-savvy group for an _asset trading_ company. And reading the article, they apparently "trade" (pun intended) in quite a few different things from CSS to OCaml, which is really nice to see for a place that doesn't directly deal with software as their [business] product (or did I misunderstand their market?).
They are basically the main company driving OCaml development outside INRIA, and the main authors behind Real World Ocaml book (https://dev.realworldocaml.org), which followed up a similar one for Haskell.
If you want to learn about Jane Street:
1. Watch Stand-Up Maths and Numberphile videos on YouTube and do not skip the sponsor advertisement readings, e.g. https://youtube.com/watch?v=eqyuQZHfNPQ .
1. Read https://news.ycombinator.com/item?id=44480916 .
Jane Street is a technology company first and foremost whose main product is high frequency training, which is similar to mang of these neo-hedge funds (e.g. HRT, Citadel). Which is contrasted to the more established asset managers (e.g. BlackRock, Vanguard, BRK, etc) which I can say from experience are corps tied down in bureaucracy.
The Economist's take https://www.economist.com/finance-and-economics/2025/06/26/j...
https://archive.ph/6Pn0K
> which is really nice to see for a place that doesn't directly deal with software as their [business] product
Part of Jane Street's business is HFT, and software is the "product" of HFT firms, because without extremely low-latency software (and hardware) they cannot make money.
And of course let's not forget what the most infamous intern of Jane Street wrought!
How many of these projects are actually merged to master and live though? I noticed the phrase "worked on" a lot, as opposed to shipped.
My interns always got very speculative projects, the kind that were low probability of working out so didnt want to waste (more valuable) time exploring. If they ever found anything useful it was 100% reworked from scratch.
My preference was for both sides to learn at the end of the day.
One of my favorite experiences was that as an intern I shipped what I thought was a useful tool. When I came back full time a year later it had spread and was pretty popular among a subset of the company!
https://news.ycombinator.com/item?id=44480916
https://www.cnbc.com/2025/07/04/indian-regulator-bars-us-tra...