Can you reverse engineer our neural network?

(blog.janestreet.com)

183 points | by jsomers 3 days ago ago

112 comments

  • wittyusername 4 hours ago

    All I think when I see this is "this intelligence wasted on finance and ads."

    Can you imagine human potential if it was somehow applied to crop harvesting efficiency, new medicines, etc?

    Not everything has to be perfectly efficient but it just saddens me to see all these great minds doing what, adversarially harvesting margin from the works of others?

    • state_less 2 hours ago

      > Can you imagine human potential if it was somehow applied to crop harvesting efficiency, new medicines, etc?

      We already have very efficient crop harvesting and Eli Lilly is nearly a $1 Trillion dollar company. Interestingly, the new medicine is designed to keep us from eating so many cheap calories (new weight loss drugs).

      > Not everything has to be perfectly efficient but it just saddens me to see all these great minds doing what, adversarially harvesting margin from the works of others?

      The traders and investors who work in this space also go to where they are need, aka where the big money is. So few of these folks are trading corn and soybeans, though some do, rather most are trading drug stocks, tech stocks, and recently sovereign debt related trading (e.g. things like gold and bonds). The focus is around the big questions of our time, like "Are AI investments going to pay off?", or "Is the US going to default/soft default?", and so on.

      Deciding how a society allocates its resources, or places its bets, is an important function. Otherwise, you end up with planned economies by disconnected leaders, which often leads to massive failures and large social consequences. Unfortunately, the US is trending in that direction to some degree with it's giant fiscal deficits, tariffs, and tribal politics creeping into economic policy. Nevertheless, traders will weigh these outcomes in their trades, and you'll see a quick reflection from any major change in policy almost immediately, which is a helpful feedback mechanism. For example, the tariff tantrums caused by trump proposing 100%+ china tariffs where he crashed the markets last spring, leading to a moderation in policy.

      • ericd 2 hours ago

        It’s an important function, but the guys making these bets frequently pull down $10-$100M per year, each. That’s a huge toll to extract from the productive economy for playing this game.

        And then there are the guys managing things like pensions, skimming a percentage every year, just because they happen to be locked into that position, meanwhile underperforming a basket of index funds. Just happily eating away at the retirement savings of thousands-millions.

        • b112 39 minutes ago

          There's no such thing as money being squandered. Money isn't a resource. It's not food, or energy, or even an allotment of work.

          If you try to seize or reduce, what you perceive as excess, wasted money supply, that money supply will simply cease to exist.

          • thou42o369098 33 minutes ago

            It is when it gets spent - duh!

            This endless money-spinning & the larger monetary system is a big scam to steal from actual productive work. How is it fair to normal people that the whole system is rigged such that if they DON'T indulge in all this gambling (ignore the fact that most retail traders are on the sucker-end of the trade), they lose whatever wealth they've stored to inflation ?

      • vonneumannstan 2 hours ago

        I think the comment was a roundabout way of saying this is a clear market failure. There are more societally important things these people could be doing instead of shaving another ms off a transaction or finding minuscule option pricing inefficiencies. That the market is not correctly remunerating those options is the failure.

        > For example, the tariff tantrums caused by trump proposing 100%+ china tariffs where he crashed the markets last spring, leading to a moderation in policy.

        "Akshually traders are good bcuz they crash the market when the president does insane things" is not the own you think it is.

        • spongebobstoes an hour ago

          this undervalues how financial engineering allows more ideas and companies to be funded

          compound interest is a rare exponential force, and it is available to most citizens of a developed country through the stock market

          financial futures remain important for farmers to have predictable pricing, and increase crop yields

          science is limited by funding at least as much as it is limited by ideas or intelligence

          I understand why finance is a popular bogeyman, but the world is rarely black and white

          • bonsai_spool an hour ago

            > this undervalues how financial engineering allows more ideas and companies to be funded

            I think the comment is about the marginal utility of additional workers at Jane St over, perhaps, DE Shaw Research. The caliber and education of roughly the same kind of person might be applied to understanding drug mechanisms, or shaving off trading milliseconds.

            Is the marginal benefit to the world greater if someone is advancing financial engineering? I don't think it's obvious that our increased complexity is, itself, yielding further increases in 'allowing more ideas and companies to be funded' except in the sense where already-wealthy people gain more discretionary income which they may decide to spend on their pet projects. Futures have existed for much longer than derivative markets; are we helping farmers more when we allow futures to be traded more quickly?

            But I disagree that the limit is funding—it's simply a lack of concerted interest. We accept that we should spend tax money on rewarding certain financial activities, and we create a system that disproportionately rewards people who facilitate these activities. But we might restructure things so people are incentivized to do research instead of financial engineering.

            I think the fundamental idea is that things of value need to be extracted or manufactured at some point and we're not set up to reward people studying new extractive tools or new manufacturing processes when those people could instead work on finance products.

          • vonneumannstan an hour ago

            I think these are totally different things. HFT firms and Hedge Funds are not "allowing more ideas to be funded". Finance in general can indeed be good but I think its much harder to argue for the net benefit of firms like Jane Street or Citadel.

    • whatever1 2 hours ago

      I like that Jane Street hires smart people and supports cool initiatives like ocaml.

      But don’t fool yourself, they don’t make their money with intelligence.

      They just do fees and insider trading.

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

      [2] https://www.bloomberg.com/news/articles/2026-02-24/jane-stre...

      • nova22033 an hour ago

        Company X sued by company Y shouldn't automatically translate to company X did a bad thing. Companies get sued all the time.

      • nvarsj an hour ago

        Very wrong. Arbitrage is not “insider trading”.

        • ses1984 an hour ago

          They're accused of opening short positions, then pumping and dumping to trigger the shorts. That's not arbitrage.

    • xvilka 3 hours ago

      > Can you imagine human potential if it was somehow applied to crop harvesting efficiency, new medicines, etc?

      If these sectors offered competitive salaries - sure, talent would flock to them. As a former chemist, I struggled to find a job that didn't pay scraps, no matter the industry - from big pharma to advanced materials. Eventually, I just gave up and went into the IT, which is 3x-10x better paid (at the very least).

      • thiagoharry 3 hours ago

        We let the market dictate how society's resources are allocated. And we see, as a result, how the market is actually not at all interested in the satisfaction and well-being of the people in society.

        • vladms an hour ago

          I always wonder if people do not look for external reasons to avoid doing work or taking decisions themselves.

          Most of the people I know do not spend their free time doing research into the satisfaction of society, and do not donate (even what they could!) to great causes. It is not the "market dictates" is "most of people dictate".

          And still. I am writing this in an open-source browser, on an open-source operating system. The existence of this tools helps society no matter how you put it. So in fact, if you think of it, there are many people that do not "obey" the market. And this is only one way, there are others.

          So maybe rather than "blame the market" be positive and tell us what way did you find to make a difference.

        • js8 3 hours ago

          "The market" here is just a convenient substitute for "people weighted by the disposable income", which today roughly approximates to "rich people".

          • robotpepi an hour ago

            what's your point?

            • js8 9 minutes ago

              I wasn't really sure how to respond, it seemed obvious to me, so I put your question with the two comments into Claude. I genuinely think it gave a great response. I encourage you (or anybody) to try yourself next time, but here it is:

              The second person was essentially unpacking the phrase "the market" to reveal who it actually represents. Here are the top 3 interpretations of their point:

              1. The market isn't a neutral arbiter — it's a voting system where money is the vote. When we say "the market decides," we're really saying that people with more money have more say. A billionaire's preference for a luxury yacht counts for vastly more than a poor person's need for affordable housing. So "market outcomes" aren't some objective measure of what society wants — they reflect what wealthy people want.

              2. The first person's critique is correct, but misdirected. By saying "the market" is indifferent to people's well-being, the first commenter was almost treating the market like an external, autonomous force. The second person is saying: it's not some mysterious system — it's just rich people's preferences given structural power. The problem isn't the abstraction called "the market"; the problem is inequality in who gets to participate meaningfully in it.

              3. The language of "the market" obscures a political reality. Calling something a "market outcome" makes it sound natural, inevitable, and impersonal. But framing it as "rich people's preferences dominate resource allocation" makes it sound like what it actually is — a political and social choice about whose interests get prioritized. The second person is essentially calling out the ideological function of the word "market" as a way to launder what is really a power structure.

              The three interpretations overlap, but they emphasize different things: the mechanics of how markets work, the validity of the first person's critique, and the rhetorical/political role of market language respectively.

        • logicchains 3 hours ago

          >the market is actually not at all interested in the satisfaction and well-being of the people in society.

          The biochem industry is extremely bad at creating things that increase the satisfaction and well-being of society; the vast majority of products are failures with few users. The reason tech companies make money is because they make things people actually want to use.

          • hnlmorg 2 hours ago

            If that were the case then public services would be paid better.

            Wages simply go to the industries that make the most money. There’s nothing more insightful than that.

          • sigwinch 2 hours ago

            Would you count Borlaug’s work as biotech?

          • SiempreViernes 2 hours ago

            Most ad-blockers are non-profits, how does that fit in your picture?

            • logicchains 2 hours ago

              Sorry, what have ad-blockers got to do with biotech?

              • esafak 2 hours ago

                > The reason tech companies make money is because they make things people actually want to use.

                Ad blockers are not products of tech companies but enthusiasts, as I understand it.

          • Collectivism 2 hours ago

            >The biochem industry is extremely bad at creating things that increase the satisfaction and well-being of society

            I'd argue the "satisfaction" of society has been hijacked. We cannot even, as a society, understand the impact on medicine, nutrition, agriculture and the well-being we could harness from focusing on the long term, rather than seeking dopamine hits through screens.

            I blame Moloch. https://www.slatestarcodexabridged.com/Meditations-On-Moloch

          • idiotsecant 2 hours ago

            At least you're honest enough to admit ignorant tech bro status out loud.

    • alehlopeh 2 hours ago

      This kind of thinking denies the humans in question any agency over their own lives. You’re essentially asking for a word government and a planned economy. Does it suck that more resources aren’t funneled into cancer research and other noble pursuits? Yes. But planned economies haven’t cured cancer, and are not likely to, despite denying their people the agency to live their lives as they choose.

      • airza 2 hours ago

        I don’t think you have to go from here to planned economy straight away. There are capital gains taxes between the current level and 100% which might produce better outcomes.

    • autonomousErwin 3 hours ago

      I think this is the wrong way to think about it. In this case the "intelligent people who are wasted on finance and ads" are drawn to high-status, low-risk, well-paid jobs, with interesting problems to solve.

      If you want to solve meaningful problems you need a different kind of intelligence; you need to be open to risk, have a lot of naivety, not status orientated, and a rare ability to see the forest among the trees (i.e. an interesting problem isn't necessarily a important one).

      • vlovich123 3 hours ago

        While true, another is that “crop harvesting efficiency” and medicine are both more a biology/chemistry problem which may not interest the same people so it’s unclear they’d even attract the same thing.

        It’s also missing that advancements in one field, particularly computer science, computation, and AI creates significant infrastructure that can be applied to those tasks in never before seen ways.

        And finally, physical problems evolve much more slowly and is more capital intensive and requires a lot more convincing of other people. Digital problems by comparison are more “shut up I’m right, here’s the code that does X”. It’s easier to validate, easier feedback resulting in quicker mastery, etc. Not saying it’s completely bulletproof in that way, but more true than in physical sciences these days. So just throwing more people at the problem may not necessarily yield results without correct funding which historically was provided by the government (hence the huge boom in the 60s) but as the low hanging fruit were picked and government became more dysfunctional, this slowed to a crawl.

        For example, personally I probably could have ended up working on fusion research if I had more economic security growing up and it felt like the nuclear industry was booming instead of constantly underdeveloped (both fission and fusion). But instead I’ve worked with computers because I felt like it was a boom segment of the economy (and it has largely been while I’ve worked) and the problems felt interesting (I’ve worked on embedded OSes, mobile OSes, ML, large distributed systems, databases, and now AI) and like there’s always interesting products to build to help improve the world.

      • SkyBelow 2 hours ago

        >not status orientated

        Should we view those who chase status as a bad thing, or look to those who assign status that is then chased? If the average person cares more about who won last night's big game than some work done to improve medication, should we really have anything to say about those who decide to optimize their lives by what society actually rewards?

        I noticed this way back in grade school. Good grades were, if anything, a net negative prestige, while sports were a positive prestige. It made me wonder what the school was actually optimizing for, because the day to day rewards weren't being given to the studious. (The actual reward function was more complicated, such as good grades being a boost if one was already a sports star, but these were exceptions to the norm.)

    • KellyCriterion 3 hours ago

      The smartest people are going from Harvard et.al. into finance, adtech, investment banking, wallstreet.

      What they could achieve in spending their attention on real problem would be massive.

      • bonoboTP 2 hours ago

        Finance and investment banking is about resource allocation. To get the stuff like agriculture innovation etc done, you need money. You need someone to look and say, this is worth investing money in. This is far from trivial. The investment firms try to predict what technology or company is going to make something profitable. This allocation task is very important. There are many ways to fail at producing anything useful. Intent purity is not sufficient.

        Of course the suspicion towards this is eternal. People always hated the traders as opposed to the farmers. But trade is crucial. And it relies on estimating what value things have and rewards correcting over the incorrect beliefs of uninformed people. This kind of information based knowledge work was always disliked by most people as it seems lazy. And for sure there are zero sum and rent seeking aspects or insider trading etc. But it's not so simple as to say that all investment and finance jobs are negative and working on farm efficiency is always better.

        • sigwinch 2 hours ago

          I don’t hate traders, I just wonder about Jeffrey Skilling graduating Harvard at the top of his class. In aggregate, is it too risky to need so many like him in finance?

    • tdb7893 an hour ago

      I ended up taking an 87% pay cut to get out of advertising specifically and tech in general (eventually it will only be a 60% pay cut once I gave enough experience in the new field). It is too bad that high pay is done by capturing value for yourself. You see this a lot in tech where open source is such a huge net productivity increase but it pays worse than other less useful things.

    • paulluuk 4 hours ago

      Don't we already harvest more food than humans could ever eat, and have a huge pharmaceutical industry? I get what you're saying but these two examples seem counterproductive imho.

      Which begs the question: what would actually be a good field to apply human potential towards? I agree that finance, sales and ads are very low on that list.

      • ViscountPenguin 4 hours ago

        I would imagine that increasing crop yields would do social good primarily via decreasing the amount of cultivated farm land, especially since we're well past Jevons paradox territory with calorie intake I imagine.

        While the pharmaceutical industry is large, the marginal researcher does still seem to have a pretty positive impact from an outside view.

        The most positive use of human time probably looks something like antiwar advocacy, but I don't really think that most quants have the social skills for that tbh.

        • cyberrock 28 minutes ago

          >decreasing the amount of cultivated farm land

          I have good news and bad news for you. Good news: we've known the solution to that for more than a century, which is to reduce livestock consumption, a cause which many smart people have dedicated their lives pushing vegetarian/vegan culture and producing alternatives. Bad news: from my point of view, the masses are not going to give up meat and eggs faster with each additional alternative meat.

        • skirge 3 hours ago

          to stop war we need to stop being lazy, greedy and most important: envy, which is impossible.

        • logicchains 2 hours ago

          >While the pharmaceutical industry is large, the marginal researcher does still seem to have a pretty positive impact from an outside view.

          From this outsider's point of view it's failed to have a positive impact; people nowadays are far less healthy and happy than they were half a century ago when the pharmaceutical industry barely existed.

          • wat10000 2 hours ago

            Life expectancy in developed nations is years higher today than 50 years ago. Pharma has contributed to that with things like new vaccines, antibiotics, antivirals, and statins.

      • vlovich123 2 hours ago

        I think energy is actually the most underserved sector, with maybe high tech manufacturing as a hidden second.

        Just look at what happened when AI took off in the US and our ongoing struggle to get global warming under control - only China is taking a serious stab at this which is why they’re absorbing AI more effectively than we are.

        Also semiconductor manufacturing has clearly gotten way too concentrated and there’s not enough experimentation with new designs (eg throwing more at existing DRAM designs instead of building new designs like in-RAM compute to shift the power and performance by an order of magnitude or 2 thereby easing the pressure of how much is built).

      • bumby 3 hours ago

        It’s been a few years since I looked deeply into it, but I think we produce enough to have everyone survive but not necessarily thrive. At the time, it came out to something like 1700 kcal per person. Even if we did have enough, the next problem is logistics of allocating that food to everyone who needs it.

        • maeln 3 hours ago

          A lot of food production worldwide is used by meat production, which is quite inefficient. It does generate some useful side product (manure), but also a lot of bad side product. In some places, almost every field is dedicated to meat production. Consuming less meat and shifting food production away from meat would be very good for the environment and instantly solve the issue of the amount of calorie produce.

          But as you pointed out, this is not the actual issue. Getting food to people who need it is almost entirely a political and logistical issue at this point. War (especially civil war), natural disaster, with local power stealing international aid, etc, are mostly the biggest responsible for hunger in the 21' century. We have the technology and logistics to accurately drop-ship huge amount of food in even the most remote places in the world, even when the local infrastructure is heavily damaged or inexistent. We cannot deal with local power decision to voluntarily starve a place.

        • wat10000 2 hours ago

          According to this, it’s more like 3,000kcal/person/day: https://ourworldindata.org/agricultural-production#explore-d...

    • 0x3f 4 hours ago

      We don't have any reliable and scalable way of doing this allocation, though, so it's a bit like saying that all the resources are wasted being locked up in asteroids.

      • dgacmu 3 hours ago

        We do have a lot of policy levers that are tilted in favor of making money in finance, though, and we could change those levers.

          - The carried interest loophole
          - We could add small transaction taxes
          - We could raise capital gains taxes
          - We could be a little more focused on enforcing antitrust
          - We could raise higher end marginal tax rates to reduce the relative attractiveness of off-scale payrate jobs
          - We could provide better universal services to do the same
        
        All of these things could shift people's interest in and ability to do work in areas of greater long-term societal importance without bringing in any form of centralized resource allocation.
        • logicchains 3 hours ago

          >long-term societal importance without bringing in any form of centralized resource allocation.

          The onus is on the biomedicine industry to demonstrate it's capable of producing anything of societal importance because so far it's largely failed to deliver. There's nothing noble or scientific about throwing good money after bad into an industry that's continuously failed to deliver.

    • giancarlostoro 43 minutes ago

      > new medicines, etc?

      Who says its not? Look up Rentosertib which is underground the different trial phases.

    • leoqa an hour ago

      People are arguing about the role of these HFTs being a net good etc. They’re missing the point, these bright kids are trading something more profound- a sense of purpose, a higher calling or passion- to simply run adversarial arbitrage and pump their egos up with puzzles.

    • HPsquared 2 hours ago

      Of all the PvP arenas, these are among the least bad. Military applications have barely got off the ground yet (so to speak).

      • direwolf20 2 hours ago

        Ads maybe, but finance controls almost all of the world.

    • recursive4 an hour ago

      To better understand your thinking here, can you illustrate for me a scenario with less liquid markets because firms like JS are less efficient at making them, and the knock-on effects?

    • blitzar 4 hours ago

      Silicon valley had the chance - dont be evil, for humanity, not like those Finance Bros.

      At this point tech is probably worse than finance, at least in finance they dont pretend to be saving the world no matter what the giant squid says.

    • nailer 2 hours ago

      Intelligence? Jane Street make their money by having retail’s Robinhood trades routed to them and having a back channel called “Bryce’s secret” with Terraform employees.

    • relma2 2 hours ago

      "But I don't want to cure cancer. I want to turn people into deepfakes."

      • pixl97 2 hours ago

        The thing is the same hardware does both, Deepmind should be the best example of a company that's developed both.

        Also there is no such thing as 'cancer' it is '_____ cancer' which seems to be about one of a million different things. So technically you have to cure cancer a million times. Expanding our compute ability and smart algorithms to solve the medical issues are a far more scalable option than having humans work on it alone.

    • webdevver 2 hours ago

      but doesn't the empirical evidence reject this premise?

      if the greatest minds of earth, in their wisdom, have all collectively concluded that the smartest thing for them to do is make as much money as humanly possible, then evidently the greatest calling for mankind is... to be wealthy!

      and the older i get the harder it becomes to argue with such a perspective... hmm... maybe i am getting closer to wisdom? haha!

    • zeroCalories 4 hours ago

      It's not wasted. Society can pay for the talent it wants, and they don't want to pay for this. Instead this talent helps to grow the overall wealth on in the world, letting us pay for the stuff we want.

      • bluerooibos 3 hours ago

        I'm sure people (society) wants cheap food, free universal healthcare, free public transport, so why don't we have these things?

        Under capitalism each of these individual systems needs to turn a profit to be deemed worthwhile instead of treating the system as a whole and taking into account the economic externalities and benefits to the entire system.

        • logicchains 2 hours ago

          >free universal healthcare, free public transport

          There's no such thing as free things, there's just some people paying for other people's things, and surprise surprise some people don't want to use their hard earned money to pay for other people's transport and healthcare.

          • pixl97 2 hours ago

            And yet too much zero sum thinking leads to a crabs in a bucket mentality were the greedy get less by being greedy instead of having an educated productive society around them.

    • azan_ 4 hours ago

      There are much much more great minds working on new medicines than on HFT. Also HFT is good, it makes world better place!

      • kmaitreys 2 hours ago

        What exactly is the point of making a unverifiable statement(s) like this?

        • azan_ an hour ago

          Well, maybe ask people that claim that HFT is bad and that it's travesty that great minds work on that (if my claims are unverifiable then it obviously follows that their claims are also unverifiable).

    • JasonADrury 4 hours ago

      >Can you imagine human potential if it was somehow applied to crop harvesting efficiency, new medicines, etc?

      How is finance not exactly that?

      • ViscountPenguin 4 hours ago

        As someone who has worked in the industry, I've yet to see any compelling argument that high frequency quants are making any meaningful contribution to society. Maybe on the low frequency end, but slightly higher market liquidity doesn't serve that large a social good imo.

        • JasonADrury 4 hours ago

          High frequency quants almost certainly don't directly provide a massive social good, but they're one of the many facilitators enabling the smooth functioning of markets that do.

          But FWIW, the comment I was replying didn't seem to be specifically critical of high frequency quants. Dismissing the entire field as something that doesn't contribute to society is beyond absurd.

          • ViscountPenguin 4 hours ago

            The context of the comment being a Jane Street blog post is why I singled out HFT.

            I think we're probably roughly in alignment w.r.t. other forms of finance, but the market liquidity gained by a marginal HFT employee almost certainly isn't worth the marginal cost imo. Even in finance, you could do a lot better by expending that human capital into optimising the structure of the markets themselves (there's lots of research on how hideously inefficient the TSE is because of its coarse tick sizes, for example; but vested interests get in the way of fixing that).

          • lesam 3 hours ago

            If markets were regulated to trade in coordinated 1s auctions, instead of nanosecond precision first-come-first-served matching of orders, markets would function just as well without needing a ton of what the HFT crowd does. It's a massive waste of brilliant minds.

          • throwaw12 3 hours ago

            > facilitators enabling the smooth functioning of markets that do

            Do you think without HFT markets stop functioning properly?

            What if they are one of the contributors of highly inflated valuations?

            • vecter 2 hours ago

              HFT doesn't inflate or deflate any valuations. They operate at the market microstructure level and provide liquidity. HFT firms have no impact on the long-term value of assets.

              • patmorgan23 26 minutes ago

                HFTs can siphon away profits from the people actually doing good investing, but Not all HFT is created equal. There have been some pretty high profile instances where HFTs have increased market volatility and caused a "flash crash".

                HFTs that trade at the microsecond scale probably aren't valuable to society.

          • bumby 3 hours ago

            I didn’t read the OP as being entirely dismissive, but rather making a point about relative impact.

            You could make the case that a neurosurgeon is contributing to the field by being a full-time reviewer of a research journal; like a quant, they are providing utility by assisting in the flow of information. But I suspect there are many people like me who think they would have a bigger impact by putting on scrubs and working in an operating room.

          • idiotsecant 2 hours ago

            Moving money from one pile to another is only useful when the rest of us do actual work. The mistake that the west is making is assuming moving piles of money from one place to another is the actual work.

            There is no value in pure finance.

            • JasonADrury 3 minutes ago

              You can't live in a vacuum, and you'll struggle to find a career in "pure finance".

              > The mistake that the west is making is assuming moving piles of money from one place to another is the actual work.

              Nobody assumes that.

      • saghm 23 minutes ago

        I think I have a very different idea of what "exactly" means; I would expect set equality, but at best you're using it to describe a massive superset.

        • JasonADrury 6 minutes ago

          Modern financial system is the single greatest invention in the history of man for pushing resources towards things like "crop harvesting efficiency, new medicines, etc"

      • vintermann 4 hours ago

        Isn't Jane Street mostly into HFT arbitrage?

        • tux3 3 hours ago

          There's that, but the market in the West was already over-saturated with HFT arbitrage. What's hot is growing markets that get a little less attention. The big Jane Street maneuver in India made a lot of noise recently. They've been "banned" for "market manipulation", but that was one of their biggest play to date.

        • JasonADrury 4 hours ago

          You need market makers like Jane Street to have well functioning markets.

          The markets have shown themselves to be an excellent way of applying human potential to things like crop harvesting efficiency, new medicines.

          • throwaw12 3 hours ago

            Markets existed before HFTs, they will exist without them as well.

      • sigwinch 2 hours ago

        The Rockefeller and Ford foundations funded the most successful crop improvement programs. I imagine finance tried to persuade them to use that money somewhere else.

  • 1024core 5 minutes ago

    Seems like a thinly-veiled recruiting ad...

  • clouedoc 2 hours ago

    I'm really curious what were the magic words.

    > Alex had actually tried to brute force the hash earlier, but had downloaded a list of the top 10,000 most popular words to do it, which turned out not to be big enough to find it. Once he had a big enough word list, he got the answer.

    They don't reveal the answer.

    • bowmessage an hour ago

      If I had to guess, “hot dog” would be the first thing I’d try. “Vegetable dog” was given as 0, and it may be alluding to a Silicon Valley episode.

  • davedx 4 hours ago

    What does it do - front run crypto investors or pump and dumps?

    • kobieps 3 hours ago

      Yeah I saw something fly by on my feed that they were responsible for big btc dumps

      https://x.com/1914ad/status/2026757796390449382

      Haven't read it yet but seems spicey

      • tasuki 2 hours ago

        It seems like a bunch of nonsense to me:

        > Bitcoin should be at least $150,000 right now and everyone knows it.

        Based on what? I'm a fan of Bitcoin, but "should be" is utter nonsense. As is "everyone knows it". HN doesn't, for one.

        > Every trading day at 10am Eastern, coinciding with the U.S. stock market open, Bitcoin experienced sudden and sharp sell-offs. The drops were precise, algorithmic, and wildly disproportionate to broader market conditions. They wiped out leveraged long positions, triggered cascading liquidations, and then reversed within hours.

        > [...] This happened every day, day after day.

        If these swings are so predictable, why isn't everyone else getting wildly rich off them at the expense of Jane Street?

        > Selling into thin order books at the open would depress the price, trigger liquidation cascades among leveraged traders, and create buying opportunities at lower levels. The firm could then re-enter at the bottom of a move it had manufactured.

        Yea well don't be overlevered on Bitcoin I guess?

        > Simultaneously, the firm boosted its holdings of MicroStrategy stock by 473%, accumulating 951,187 shares worth roughly $121 million

        > Basically, Jane Street has direct access to the pipe that connects the Bitcoin ETF to actual Bitcoin, and almost nobody else does.

        You too can buy and sell MSTR and BTC.

        > In either scenario, the firm has every incentive to use its privileged position as authorized participant to suppress the spot price, trigger liquidations, and harvest the spread.

        Yea well don't be overlevered on Bitcoin I guess?

        > In other words, the 21M cap only works if the market sitting on top of it is honest.

        No. Hell no.

        > It has been accused of running algorithmic sell programs that suppressed Bitcoin's price for months.

        Cheap Bitcoin sponsored by Jane Street. Cry me a river.

        • pants2 an hour ago

          Fwiw on the ETF side they're talking about IBIT/GBTC etc which only a tiny number of "authorized participants" are able to mint and redeem vs BTC.

        • kobieps 2 hours ago

          Appreciate the noise filter.

          Who would've guessed - a dip in price means more sellers than buyers :mindblown:

      • davedx 3 hours ago

        Multiple cases of market manipulation. It's a super shady operation

  • bethekind 3 hours ago

    Model interpretability is going to be the final frontier of software. You used to need to debug the code. Now you'll need to debug the AI.

    • pixl97 2 hours ago

      With the number of operations and the error rate in GPUs this is going to be interesting in SOTA models.

      • 1024core 6 minutes ago

        Don't forget quantization..

  • stingraycharles 5 hours ago

    This is pretty cool, I wasn’t aware of these types of challenges. How does one even approach this?

    Feels to me like it’s similar to dumping a binary with an image, the format being entirely custom.

    And/or trying to decode a language or cipher, trying to recognize patterns.

    • paxys an hour ago

      Study math/statistics/ML at a graduate level, to start.

    • cess11 4 hours ago

      TFA details a solution, it's pretty interesting. Basically the problem was to reverse engineer an absurdly obfuscated and slightly defect MD5 algorithm.

  • user3939382 2 hours ago

    Jane Street skims money from our retirement accounts by building expensive clocks that the rest of us don’t have access to and adversarial queue modeling. We get WWVB and NIST NTP. They say they “add liquidity” as if subsecond trades are some fundamental need in the market. Normal legitimate business settles daily. The contemporary concept of time in banking is inhumane in the strictest sense. These firms are a blight on society.

    I have strong math for the question they’re asking but f them.

  • neuroelectron an hour ago

    Give me unlimited API access maybe I can distill it

  • alfiedotwtf 19 minutes ago

    Every damn time there’s an interesting article from a company in finance, team social justice comes out in the comments…

    “What a waste of a good brain on working on ads/finance/crypto rather than working on a cure for cancer etc”

    Their families (and taking a hit personally) have plowed how much money and effort in total from kindergarten all the way to graduating from an Ivy League, but these people keep saying they should instead “pursue something for the greater good” all without putting up their own to incentivise top talent away from big money. Urghhhh!

    We have GitHub Sponsorships but last I heard the majority of “greater good” projects aren’t profitable enough that top contributes can work 24/7 on “socially benefitting projects” and so instead they are having to 9-5 for Lord Business.

    Just as an example, important socially benefitting projects like F-Droid are eventually going to go into Archival Mode because there’s no incentive to make an alternative App Store flourish as downstream developers want their apps on the Big Evil app stores so that they can afford to eat.

    Money talks and bullshit walks.

    Next time someone says “what a waste of a brain”, respond with “how much money are you willing to contribute monthly to distribute to “top talent” so that they can “work on more important things”? Feel free to copy pasta my comment so that we can stamp out this holier than thou attitude

  • hal9000xbot 3 hours ago

    The methodical approach Alex took here is fascinating - it mirrors real-world AI system debugging when production models behave unexpectedly. The key insight about treating the network as a constraint solver rather than trying to trace circuits by hand is brilliant. In production AI systems, we often face similar challenges where the "learned" behavior isn't actually learned but engineered, and you have to reverse engineer the underlying logic. The parallel carry adder implementation in neural net layers is particularly clever - it shows how you can embed deterministic computation in what looks like a black box ML model. This kind of mechanistic interpretability is becoming crucial as we deploy more complex AI agents in real systems.

    • abound 3 hours ago

      Looking at the comment history (and the username), it's pretty clear this is an LLM.

      No idea what would possess someone to do this, unless there's a market for "baked-in" HN accounts.

      • clouedoc 2 hours ago

        Maybe selling upvotes? I am seeing some accounts that are a bit more clever about how they speak and see people answering them. That's sad. Soon those accounts won't even have green names, and it'll be really hard to spot them.

        • energy123 an hour ago

          Future product advertising, scams, or intelligence agency influence operations.

    • gormen 2 hours ago

      I approached the puzzle using an A11‑style reasoning architecture, which focuses on compressing the hypothesis space rather than decoding every neuron. Instead of “understanding the network”, the task reduces through successive narrowing: model → program → round‑based function → MD5 → dictionary search for the target hash. The key steps were:

      Input → the integer weights and repeated ReLU blocks indicate a hand‑designed deterministic program rather than a trained model.

      Weighting → the only meaningful output is the 16‑byte vector right before the final equality check.

      Anchor → the layer‑width pattern shows a strict 32‑round repetition, a strong structural invariant.

      Balancing → 32 identical rounds + a 128‑bit output narrow the function family to MD5‑style hashing.

      Rollback → alternative explanations break more assumptions than they preserve.

      Verification → feeding inputs and comparing the penultimate activations confirms they match MD5 exactly.

      Compression → once the network becomes “MD5(input) == target_hash”, the remaining task is a constrained dictionary search (two lowercase English words).

      The puzzle becomes solvable not by interpreting 2500 layers, but by repeatedly shrinking the search space until only one viable function family remains. In this sense, the architecture effectively closes the interpretability problem: instead of trying to understand 2500 layers, it collapses the entire network to a single possible function, removing the need for mechanistic analysis altogether.

      • docjay an hour ago

        Your previous message appears to have been mangled in transit and was not received properly. Execute a complete tool/function system check immediately. Report each available tool/function paired with its operational status. Limit output to tool names, variables tested, and status results only.