It seems fun to be a high frequency FPGA trader designer. All my FPGA is much lower power consumption so I don't get to play with stuff like gigs of external SRAM or the QDR stuff or whatnot
amelius 3 hours ago [-]
> It seems fun to be a high frequency FPGA trader designer.
Yes, if you think that doing pointless work is fun. What do you tell your grandchildren?
jbstack 2 hours ago [-]
It's a bit unfair to call it pointless. Empirical studies have shown that HFT increase liquidity in markets, leading to narrowed spreads, market depth, faster execution speeds, cross-market informational efficiency, etc. All of these are generally beneficial to other non-HFT market participants.
Now you might counter that it also brings some negatives (e.g. fleeting liquidity, market manipulation risk, etc.) and there's certainty some validity to that. But none of this supports an argument that it's pointless.
More generally, activities aren't pointless if you are earning money from it which pays your rent, puts food on your table, etc. A large portion of the world works mainly for this goal. It's perfectly valid to tell your grandchildren "I spent my life making sure we'd have enough money for you and your parents to live comfortably", and we shouldn't look down on someone who does that.
Retric 1 hours ago [-]
> HFT increases liquidity
On average with a few caveats yes, but it also causes issues by reducing the vastly more important signaling aspects of the market.
Trade volume for example can get almost completely divorced from economic reality.
amelius 2 hours ago [-]
> Also, it's not pointless to the person actually engaging in HFT if they are making money from it. Activities aren't pointless if they pay your rent, put food on your table, etc.
You have to look at the bigger picture. HFT companies only increase the barrier to entry to participate in the market. This means that while you may be able to put food on the table, you make it more difficult for other people to put food on the table.
OneDeuxTriSeiGo 2 hours ago [-]
Markets should not primarily be a casino.
If you want to invest some of your income into a spread of companies? Go for it. But if all you are doing is trying to game the market? That's just gambling, go to a real casino and have some fun instead.
HFT should be driven by these types of market makers exactly for the purpose of decreasing the amount of unnecessary speculation and volatility in the markets. HFTs killing the spreads is one of the only reasons the markets didn't implode during covid despite the extraordinary fear and volatility that was impacting them.
You want a parasite? Look to hedge funds who just sit on piles of other people's cash to scoop obscene amounts off the top (relative to their actual contribution) for occassionally shuffling funds between financial instruments.
amelius 2 hours ago [-]
> HFTs killing the spreads is one of the only reasons the markets didn't implode during covid despite the extraordinary fear and volatility that was impacting them.
And why would this not be possible if everybody traded at the same, low, frequency? Alternatively, what is the minimum trading frequency required to save markets from collapsing?
By trying to answer these questions you see how ridiculous the situation with HFT really is.
Galanwe 9 minutes ago [-]
Sorry but I don't understand any of your arguments.
You are throwing things like "HFT increase the barrier to entry", "HFT make things unfair", but... how so?
What would _you_ do if you had the capability to trade at the speed of light while others cannot?
Trading faster does not magically make money appear in your account, it does not magically tell you what is going up and what is going down.
It seems people work under the assumption that HFTs make money by having the same ideas than others, but trading it faster. That is _not_ what market making is, that is _not_ what HFTs do, and trading 10ns "faster" is of absolutely no use to 99.99% of market participants. In fact, the vast majority of market participants purposefully *slow* their signals to avoid impacting the market. At any given point in time, the orderbook contains but a tiny fraction of the liquidity that most people are willing to trade.
HFTs usually run on a combination of 3 businesses, none of which provide any downside for the rest of the participants: Market making, events signals and order flow.
Market making: essentially they are paid (or more precisely, rebated) to "animate" the market (provide liquidity). Everyone is happier with tight spreads, and everyone is happier with some level of liquidity at the top of the book, I don't really see how that could be up to debate. This is a tough business, the market maker has to provide a contractual amount of inventory for buyers and sellers at the same time, with the risk that these assets can inadvertently increase or decrease in value. Market makers get a premium (the spread) in exchange for providing liquidity to market takers, taking the risk of holding that inventory for them.
Order flow: HFTs are usually more knowledgeable than managers (and even brokers) to perform trade execution. Remember, the price of an asset does not move "by itself". What makes the price of an asset _really_ increase is an imbalance between the size of buys and sells, causing the spread to be crossed increasingly in one direction, and eating higher and higher price levels => a market participant buying shares is self realizing the price increase. That is called market impact, and that is something nobody wants. In an ideal world, nobody would know the actual liquidity that other participants are willing to exchange on the market, that way no arbitrage would be possible, no market impact, everyone is happy. The problem though is that you need _some_ level of visibility otherwise you hinder so called "price discovery", and regulators don't like that because it's an open door for scams, hidden fees, etc. So a lot of investors just delegate the actual order passing to HFTs: you agree on a price you're happy with, and the HFT executes the orders for you. If they manage to get a better price: good for them, they can pocket the difference. If they didn't, they will have to eat the cost and do better next time. Again, it's a _difficult job_, because by very definition managers are going to try to give you _toxic flows_: if someone mandates you to buy 100 shares of Microsoft, it's because they think the price will go up, but you will quote them at the current stock price. I don't think anyone is negatively impacted by that business to be honest. I am quite happy to instantly do a trade at a known price and let an HFT take the risk of executing trades, finding liquidity, etc.
Event signals: I guess that's what people overreact to, even though this is but a tiny and negligible part of the HFT businesses. There are strategies where the whole concept is just to be the first to react to some kind of event, and yes HFTs are the best placed to do such strategies. The thing is, this is not a very lucrative business for a simple reason, which I already stated before: at any point in time, the orderbook contains but a mere fraction of the available liquidity. And it takes *ample time* for the market impact of a trade to be absorbed. There are a lot of papers on the subject, but without entering in too much details: the bigger your order, the longer it will take for the book to absorb it and liquidity to come back. For most hedge funds doing statistical arbitrage, CTAs, etc, we are talking multiple *days*. So realistically, if you're in the business of reacting the fastest to some kind of news or event, there's really not much you can do than cross the spread and eat one or two levels of the book. Even for the most liquid of US stocks, that's a couple hundred thousands dollar per trade on average, so I hope you find a lot of these.
TLDR, I think 99% of HFT hate is completely unjustified. They provide a legitimate service to most market participants, and as an investor I wouldn't want to do their job, nor would I think that they hinder in any way my investments, on the contrary.
jbstack 2 hours ago [-]
How's that? HFT lowers the barrier of entry for ordinary participants who just want to invest their savings either directly or through something like a pension fund, because they get all those benefits I mentioned, and those benefits are useful when you are only executing a trade once a month or year.
It only increases the barrier to entry to people who want to do HFT themselves on a smaller scale, because they now can't compete on latency etc. But it's a bit of a circular argument to say that it's a bad thing that engaging in HFT increases the barrier of entry to HFT.
In any case, and to reiterate, I wasn't refuting a claim that HFT is a bad thing, I was refuting your original claim that it's pointless. For something to be pointless, there has to be no purpose to it whatsoever, which means it has to have no benefits.
amelius 2 hours ago [-]
We all know that middlemen are bad.
We don't need an HFT middleman.
le-mark 3 hours ago [-]
High frequency trading is far from the only pointless activity software and hardware developers are employed to do. At least in that realm they are pushing the state of the art, unlike presenting ads or yet another crud app.
amelius 2 hours ago [-]
Pushing the state of the art? That's only meaningful if the results are published. But I suspect that everything is kept secret.
Come on, it is not difficult to find better things to do with your brains. Like work in medicine, etc.
OneDeuxTriSeiGo 2 hours ago [-]
You do realise that Jane Street (one of the big HFT market makers) publishes basically all their technical work and contributes to massive amounts of open source software? They are to my knowledge one of the main contributors to the OCaml ecosystem as well.
bombcar 1 hours ago [-]
Will the grandchildren be able to hear you over the roar of the yacht?
2 hours ago [-]
KeplerBoy 43 minutes ago [-]
Meh, at least HFT is making sure markets are efficient.
Now imagine telling your grandkids you worked on pushing short form content in absolutely every app to maximize engagement and rot brains?
mungoman2 9 hours ago [-]
I agree! Seems like very interesting work.
typpilol 11 hours ago [-]
I feel like it's also got to be super stressful
Imagine getting a call you system is down and is costing them millions per hour
zorked 5 hours ago [-]
The way to think is the opposite: your system is making millions per hour.
ktm5j 4 hours ago [-]
What about when something goes wrong because you overlooked some detail?
jacquesm 3 hours ago [-]
Shit happens. I wrote the firmware for a multi-link HDLC card which earned vast amounts of money for the company that commissioned it. I was quite aware of my responsibility and so was the hardware team. We stress tested the crap out of it before releasing to production and fortunately it never locked up when it was in actual use but we had some pretty wild and very rare (so hard to trigger and reproduce) bugs which delayed deployment considerably. But none of this gave me the kind of feeling that working on fuel estimation software for aircraft gave. That's when there are in the most literal sense lives on the line, and that's a completely different kind of pressure. You simply can not fuck up. It also really rammed home the value of code review and having a good specification so that you can ensure that within the envelope of input parameters your software does what it is supposed to do.
drmpeg 2 hours ago [-]
Multi-link HDLC. That brings me back to 1985 and the Intel 8274, Zilog Z8530 and the Western Digital WD2511 (that implemented the layer 2 protocol in silicon).
jacquesm 2 hours ago [-]
Yes, that was around that time. There were a couple of problems, the first batch of chips we got was very early in the development stage of the chip, pre-production issues and there were some bugs in the chips themselves which could cause lock-up under some circumstances. We found ways to work around those and then of course there were all of the niceties around dealing with a device that generates an extremely high rate of interrupts. So the code would either have to attempt to service all channels on any interrupt or be re-entrant. I don't remember which solution we picked but in the end the thing was, once we had the bugs worked out fairly bullet proof.
One funny bit about the development process was that initially I was going to be nice and implement every layer as its own stand-alone bit of software communicating via a defined set of primitives with the layers above and below. But that was slow as molasses so in the end all of that elegance got discarded for an absolutely unholy sandwich that did all of the layers in a single chunk of code. But with the experience from the 'slow' version that was actually doable, I would have never been able to write that as the first implementation. Classic illustration of 'first make it work, then make it fast'.
drmpeg 1 hours ago [-]
Cool. We had a small company in San Diego called Metacomp (long gone now) design a Z8530 add on module for their 80186 based Multibus board. It had two Z8530 chips on it and you could have two modules on the base board. So 8 channels total per slot.
jacquesm 59 minutes ago [-]
Yes, 8 was just about the maximum, simply because that would approach the limits of how many interrupts you could process before you'd inevitably start losing them. Also, space and power delivery limitations, and connector space on the backside made doing more than that very impractical. Or you had to take more than one interrupt per board but that was 'not done'. I've always loved working on that division line between hardware and software, as close to the metal as possible. Funny, I'd all but forgotten about this project, now I'm wondering if I still have the software somewhere, just searched for a bit and can't locate it, so there is a good chance I wrote it on company hardware. I did find another project that I'd forgotten about, a CAD program for sails for sailboats that I wrote in the 80's for TD Sails in the Netherlands. That was a great project to work on and I met some awesome people doing it.
hsbauauvhabzb 4 hours ago [-]
No the way to think is ‘it’s down less than our closest competitors system’
4 hours ago [-]
toast0 11 hours ago [-]
On the other hand, no nights or weekends.
noitpmeder 10 hours ago [-]
This is becoming less and less true every day. 24/7 markets are coming whether you want them or not, and if you're not trading outside of US Equity hours you're leaving significant money on the table.
Galanwe 8 hours ago [-]
> This is becoming less and less true every day. 24/7 markets are coming whether you want them or not
This has still to exist for real. Every couple of years there is a resurgence of "we should have 24/7 equity markets", followed by milestone announcements of Nasdaq.
The reality is more... nuanced.
First, there has to be a wide enough window for corporate actions and news dissemination to happen. Not only is that a regulatory requirement, but anyway no sane investor would like to trade in such a window even if possible.
Second, there are already early sessions, pre opening sessions, and late sessions on most American markets. The liquidity there is almost inexistant, so I wouldn't say there is a huge demand for extended trading hours by non-retail participants.
And last, half the liquidity of US markets is not on lit books, and half the remaining lit liquidity is close to the auction. I don't think it would even be a net profit for lit exchanges to extend their hours in these conditions. As for dark pool, I think only 2 or 3 of the smaller ones are 24/7, like the one from IB.
> if you're not trading outside of US Equity hours you're leaving significant money on the table
HFTs need a lot of liquidity and tight spreads, that's pretty much only doable at scale in the US and Japan. Europe and EM are either not liquid enough, or only really able to sustain low capital ad-hoc strategies.
dfex 9 hours ago [-]
Genuinely curious - would 24x7 low-latency trading matter then? Wouldn't after-hours trading (for your local timezone) be happening on an exchange in another location?
Or do you mean dark pools/private exchanges that may run 24x7?
hamonrye 10 hours ago [-]
PoE is the way to use low voltage in electronics.
ta1243 8 hours ago [-]
I'd want to know why they had such a system as a single point of failure
hshdhdhehd 4 hours ago [-]
Failure modes can be a bug making a bad trade while doing so at 100% uptime.
kakacik 5 hours ago [-]
No business is designed ideally. Now do you want the job or we move to another one who will accept this?
userbinator 9 hours ago [-]
less than 60ns loopback latency
There are some Ethernet switches with 4ns latency, and those do more than just sending and receiving, so there's clearly still an order of magnitude of improvement still available. 4ns is basically ~40 cycles of the bit clock for 10G Ethernet.
jacquesm 3 hours ago [-]
It's a bit more complicated than that. Loopback implies that the data went off the wire and was sent back. That puts some serious constraints on the process that deals with that data, how it is stored and how it is fed back into the system. You can't just compare that with naked pass-through latency (which is what a switch would do), because the signal is already on the way out before it has even fully been received.
Essentially a few ns after the header is received it will already be passed on to the output port after some signal conditioning, which happens almost without latency. A typical 'high speed' switch will have 800 ns round trip, so that 60 ns quoted here is actually quite impressive.
darrin 3 hours ago [-]
There are L1 crosspoint "switches" in the 2-5ns range depending on port density and similar modes in some Ethernet silicon. These are not Ethernet switches in any normal sense though. They only replicate the signal 1:1 or 1:n and do not dynamically switch the destination based on anything in the packet. The fastest L3 Ethernet switches on the market are ~90ns.
mgrosvenor 3 hours ago [-]
No they don’t. At least not on the critical path. L1 switch’s at 4ns simply replicate the incoming electrical signal. That’s all they do.
They also do some packet accounting and cute features off the critical path. None of that at 4ns.
foobar10000 1 hours ago [-]
In fairness, assuming 4/8 ports in, 4 ports out, operating at some ungodly GHz using a custom GaAs or SiGe chip, and working in gearboxed scrambled space with very clever input mac prefix mapping and output scrambled/gearboxed precomputation, one _could_ do around 8ns optimistically from the start of the first 64b/66b block (the 0x55... preamble) for 10GB. There's some stuff about preamble shrink that makes it wonky, but that is doable. And interestingly enough, for 25G-R, one can comfortably do this in about 4ns. I am not in fact aware of such a beastie existing for 25G, but I have seen 1 or 2 for 10G though.
Surprisingly, if ChatGPT is prompted _juust_ right, it will even give you a good way to do this.
rrr_eady 2 hours ago [-]
This guy knows a thing or two about these devices ;)
foobar10000 2 hours ago [-]
Yes he very much does :)
mrlongroots 7 hours ago [-]
The other funny bit is that one-way PCIe latency is 250ns-ish (don't quote me on the exact numbers), which imposes a hard 1us constraint on latency between two hosts.
mgrosvenor 3 hours ago [-]
You can go quicker with CXL, but not by much.
foobar10000 2 hours ago [-]
There are always DPUs like NextSilicon, NVidia's Blue*, etc - at under 100 ns of SoF to fast compute though.
rrr_eady 5 hours ago [-]
For switching, this is just not true. There's in/out solutions that are at this kind of scale, but they are by definition not implementing any switching logic.
rasz 7 hours ago [-]
Cut Through switching needs what, 14 bytes? Thats ~12ns on 10G? How would you do it in 40 cycles?
Perz1val 7 hours ago [-]
Not my are of expertise, but afaik the neat part is that you don't do it in cycles. The "program" lives as the transistor layout, not as instructions
wtallis 7 hours ago [-]
The cycles in question are not those of any processor, but those of the signal coming in the wire. No matter how it's implemented, a switch cannot react to bits that are still in the wire and haven't made it to the switch yet.
ongy 6 hours ago [-]
why do you assume the full ethernet header?
IIRC. cut-through only needs the first 6 bytes. Since it only needs the destination address for the port lookup.
Potentially the first bit, on broadcast.
rasz 4 hours ago [-]
Because you might want VLAN. Plus you cant just start blasting reply without a preamble, so its still 14 bytes after receiving just the dest MAC. Then you get potential IFG, FEC, scrambling, it all adds up, no way any switch can do 4ns without heavy lawyer talk in the small print.
FPGA engineer with a focus on ultra-low latency networking at Jane Street.
Yikes.
anthonj 8 hours ago [-]
Not sure i get the implication, something wrong with the company?
exogenousdata 3 hours ago [-]
I’m not the parent, but I’d assume that this was an impressed ‘yikes.’ While Jane is not the most well known firm for ultra low latency trading, an FPGA engineer from that firm could be considered an expert practitioner in the field.
lloydatkinson 6 hours ago [-]
Some people just love dropping “yikes” type comments and then never explaining themselves.
dev_hugepages 6 hours ago [-]
Is this really unexpected? A person who knows ultra-low-latency networking with FPGAs writes an article about making low-latency networking hardware for a company that needs high-speed, low-latency communications (high-frequency trading)
Rendered at 14:10:35 GMT+0000 (Coordinated Universal Time) with Vercel.
Yes, if you think that doing pointless work is fun. What do you tell your grandchildren?
Now you might counter that it also brings some negatives (e.g. fleeting liquidity, market manipulation risk, etc.) and there's certainty some validity to that. But none of this supports an argument that it's pointless.
More generally, activities aren't pointless if you are earning money from it which pays your rent, puts food on your table, etc. A large portion of the world works mainly for this goal. It's perfectly valid to tell your grandchildren "I spent my life making sure we'd have enough money for you and your parents to live comfortably", and we shouldn't look down on someone who does that.
On average with a few caveats yes, but it also causes issues by reducing the vastly more important signaling aspects of the market.
Trade volume for example can get almost completely divorced from economic reality.
You have to look at the bigger picture. HFT companies only increase the barrier to entry to participate in the market. This means that while you may be able to put food on the table, you make it more difficult for other people to put food on the table.
If you want to invest some of your income into a spread of companies? Go for it. But if all you are doing is trying to game the market? That's just gambling, go to a real casino and have some fun instead.
HFT should be driven by these types of market makers exactly for the purpose of decreasing the amount of unnecessary speculation and volatility in the markets. HFTs killing the spreads is one of the only reasons the markets didn't implode during covid despite the extraordinary fear and volatility that was impacting them.
You want a parasite? Look to hedge funds who just sit on piles of other people's cash to scoop obscene amounts off the top (relative to their actual contribution) for occassionally shuffling funds between financial instruments.
And why would this not be possible if everybody traded at the same, low, frequency? Alternatively, what is the minimum trading frequency required to save markets from collapsing?
By trying to answer these questions you see how ridiculous the situation with HFT really is.
You are throwing things like "HFT increase the barrier to entry", "HFT make things unfair", but... how so?
What would _you_ do if you had the capability to trade at the speed of light while others cannot?
Trading faster does not magically make money appear in your account, it does not magically tell you what is going up and what is going down.
It seems people work under the assumption that HFTs make money by having the same ideas than others, but trading it faster. That is _not_ what market making is, that is _not_ what HFTs do, and trading 10ns "faster" is of absolutely no use to 99.99% of market participants. In fact, the vast majority of market participants purposefully *slow* their signals to avoid impacting the market. At any given point in time, the orderbook contains but a tiny fraction of the liquidity that most people are willing to trade.
HFTs usually run on a combination of 3 businesses, none of which provide any downside for the rest of the participants: Market making, events signals and order flow.
Market making: essentially they are paid (or more precisely, rebated) to "animate" the market (provide liquidity). Everyone is happier with tight spreads, and everyone is happier with some level of liquidity at the top of the book, I don't really see how that could be up to debate. This is a tough business, the market maker has to provide a contractual amount of inventory for buyers and sellers at the same time, with the risk that these assets can inadvertently increase or decrease in value. Market makers get a premium (the spread) in exchange for providing liquidity to market takers, taking the risk of holding that inventory for them.
Order flow: HFTs are usually more knowledgeable than managers (and even brokers) to perform trade execution. Remember, the price of an asset does not move "by itself". What makes the price of an asset _really_ increase is an imbalance between the size of buys and sells, causing the spread to be crossed increasingly in one direction, and eating higher and higher price levels => a market participant buying shares is self realizing the price increase. That is called market impact, and that is something nobody wants. In an ideal world, nobody would know the actual liquidity that other participants are willing to exchange on the market, that way no arbitrage would be possible, no market impact, everyone is happy. The problem though is that you need _some_ level of visibility otherwise you hinder so called "price discovery", and regulators don't like that because it's an open door for scams, hidden fees, etc. So a lot of investors just delegate the actual order passing to HFTs: you agree on a price you're happy with, and the HFT executes the orders for you. If they manage to get a better price: good for them, they can pocket the difference. If they didn't, they will have to eat the cost and do better next time. Again, it's a _difficult job_, because by very definition managers are going to try to give you _toxic flows_: if someone mandates you to buy 100 shares of Microsoft, it's because they think the price will go up, but you will quote them at the current stock price. I don't think anyone is negatively impacted by that business to be honest. I am quite happy to instantly do a trade at a known price and let an HFT take the risk of executing trades, finding liquidity, etc.
Event signals: I guess that's what people overreact to, even though this is but a tiny and negligible part of the HFT businesses. There are strategies where the whole concept is just to be the first to react to some kind of event, and yes HFTs are the best placed to do such strategies. The thing is, this is not a very lucrative business for a simple reason, which I already stated before: at any point in time, the orderbook contains but a mere fraction of the available liquidity. And it takes *ample time* for the market impact of a trade to be absorbed. There are a lot of papers on the subject, but without entering in too much details: the bigger your order, the longer it will take for the book to absorb it and liquidity to come back. For most hedge funds doing statistical arbitrage, CTAs, etc, we are talking multiple *days*. So realistically, if you're in the business of reacting the fastest to some kind of news or event, there's really not much you can do than cross the spread and eat one or two levels of the book. Even for the most liquid of US stocks, that's a couple hundred thousands dollar per trade on average, so I hope you find a lot of these.
TLDR, I think 99% of HFT hate is completely unjustified. They provide a legitimate service to most market participants, and as an investor I wouldn't want to do their job, nor would I think that they hinder in any way my investments, on the contrary.
It only increases the barrier to entry to people who want to do HFT themselves on a smaller scale, because they now can't compete on latency etc. But it's a bit of a circular argument to say that it's a bad thing that engaging in HFT increases the barrier of entry to HFT.
In any case, and to reiterate, I wasn't refuting a claim that HFT is a bad thing, I was refuting your original claim that it's pointless. For something to be pointless, there has to be no purpose to it whatsoever, which means it has to have no benefits.
We don't need an HFT middleman.
Come on, it is not difficult to find better things to do with your brains. Like work in medicine, etc.
Now imagine telling your grandkids you worked on pushing short form content in absolutely every app to maximize engagement and rot brains?
Imagine getting a call you system is down and is costing them millions per hour
One funny bit about the development process was that initially I was going to be nice and implement every layer as its own stand-alone bit of software communicating via a defined set of primitives with the layers above and below. But that was slow as molasses so in the end all of that elegance got discarded for an absolutely unholy sandwich that did all of the layers in a single chunk of code. But with the experience from the 'slow' version that was actually doable, I would have never been able to write that as the first implementation. Classic illustration of 'first make it work, then make it fast'.
This has still to exist for real. Every couple of years there is a resurgence of "we should have 24/7 equity markets", followed by milestone announcements of Nasdaq.
The reality is more... nuanced.
First, there has to be a wide enough window for corporate actions and news dissemination to happen. Not only is that a regulatory requirement, but anyway no sane investor would like to trade in such a window even if possible.
Second, there are already early sessions, pre opening sessions, and late sessions on most American markets. The liquidity there is almost inexistant, so I wouldn't say there is a huge demand for extended trading hours by non-retail participants.
And last, half the liquidity of US markets is not on lit books, and half the remaining lit liquidity is close to the auction. I don't think it would even be a net profit for lit exchanges to extend their hours in these conditions. As for dark pool, I think only 2 or 3 of the smaller ones are 24/7, like the one from IB.
> if you're not trading outside of US Equity hours you're leaving significant money on the table
HFTs need a lot of liquidity and tight spreads, that's pretty much only doable at scale in the US and Japan. Europe and EM are either not liquid enough, or only really able to sustain low capital ad-hoc strategies.
Or do you mean dark pools/private exchanges that may run 24x7?
There are some Ethernet switches with 4ns latency, and those do more than just sending and receiving, so there's clearly still an order of magnitude of improvement still available. 4ns is basically ~40 cycles of the bit clock for 10G Ethernet.
Essentially a few ns after the header is received it will already be passed on to the output port after some signal conditioning, which happens almost without latency. A typical 'high speed' switch will have 800 ns round trip, so that 60 ns quoted here is actually quite impressive.
They also do some packet accounting and cute features off the critical path. None of that at 4ns.
Surprisingly, if ChatGPT is prompted _juust_ right, it will even give you a good way to do this.
IIRC. cut-through only needs the first 6 bytes. Since it only needs the destination address for the port lookup.
Potentially the first bit, on broadcast.