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AI Engineer NYC 2026 Main stage · 14 min

A Hedge Fund as a Function

Frank LongCoatue

Frank Long models an investment firm as a function that turns external and internal context into selection, size, and timing. The engineering challenge appears when that function is decomposed into work that code, models, and people can each perform well.

Compress the world into an investment decision

7:14:23 ↗

An investment firm takes in an enormous amount of information and produces a small decision: which asset, how much, and when. Frank Long uses that compression problem to explain the AI work at Coatue.

The function takes external and internal context and returns three values: selection, size, and timing. Repeated decisions build the portfolio. Writing that down gives engineers a starting point; decomposing the function reveals how much work it contains.

The first requirement is access. Long argues that information employees can see on their screens should also be available to the firm’s agents through APIs. Hiring an exceptional investor but withholding most of the service logins would waste that person’s abilities; an agent without access has a similar limitation.

External context includes news, prices, and filings. Internal context includes current positions, liquidity and risk constraints, earlier research, and experience with a company or management team. Long emphasizes that this is a cultural accomplishment as well as a technical one. Notes about decisions taken, decisions avoided, and outcomes become useful inputs only if the organization has made a habit of preserving them.

Even gathering the news is a collection of decisions

7:17:34 ↗

Putting all that information into a context window does not produce a trustworthy investment decision automatically. Long first decomposes the function into gathering relevant information, analyzing it to form a view, and turning that view into a decision. Each step has an input and an output the next step can use.

Then he zooms into one small part of gathering: interpreting Korean-language news about semiconductors and AI. A team that does not speak Korean has an obvious reason to use models, but translation is only one piece of the system.

Articles need to be collected through some interface: a licensed feed, a CLI, or an MCP connection. The input design has choices of its own. How should the articles be chunked? Should images reach the model as images or be converted to text? These choices affect which information survives into the later stages.

The system also has to filter relevance. A Korean news source can carry sports stories alongside semiconductor coverage. After filtration come more choices: translate, summarize, extract structured data, or combine those operations. Finally, the new information needs to be checked against internal notes, prior views, and meeting records before updating the firm’s understanding.

Long treats these implementation choices as hyperparameters: settings to compare against the quality of the resulting research.

Choose the runner for each piece of work

7:21:43 ↗

A function can be performed by different kinds of runner. If the question is whether a price-to-earnings ratio is below fifteen, an ordinary comparison is fast, cheap, and dependable. Classical statistics or machine learning can capture relationships more complex than an explicit rule.

Language models become useful for tasks such as summarization, where a collection of hand-written conditions would be a poor substitute. People remain important runners too. Meeting a management team calls for judgment and real-world interaction; Long jokes that he would not send an if statement to the meeting.

The aim is to maximize the quality of each part of the process. Replacing a person or a deterministic step with an LLM has no independent value if the resulting work is worse.

This also means the architecture will rarely be a simple chain. The news workflow can branch: one route extracts quotations and checks their sources; another extracts figures and relates them to the drivers of a stock; another tests the new evidence against an existing view.

Coatue’s news-gathering diagram branches through filtering, translation, quote and figure extraction, source checks, internal comparisons, proposal, and review.

The slide at 7:24:08 makes the alternatives and feedback paths visible. Source checking can send work back when a quotation does not match. Review can revise a proposal. Internal notes join the workflow at several points rather than appearing only in one initial prompt.

Find something small enough to evaluate

7:24:38 ↗

Even the runner categories combine. Collection may use code; filtering may use a model plus rules; a human may assess portfolio implications with software helping retrieve the relevant evidence. Within the model-based steps, the team can vary model size, reasoning effort, harness, skills, and hooks.

That produces an enormous search space for just one part of one data source. Long’s response is to compartmentalize work into units the team can understand and evaluate. Without a useful objective, changing models and prompts becomes aimless tuning.

An evaluation might show that a small trained model should replace a large LLM, that a rule is sufficient, or that portfolio interpretation should remain with a person. Those are improvements if they produce better results for that step. The architecture needs to make such substitutions possible.

At the scale of an investment firm, many sources and transformations form a much larger graph. Making it comprehensible technically—and something the organization can actually adopt—is the challenge Long leaves with the audience.

The same decomposition could help with policy, drug discovery, or corporate strategy: gather information, interpret it, decide what to do. Each field would need its own tasks and standards. Start with a part small enough to evaluate, then choose the code, model, or person that performs it best.

Full transcript

Timestamps follow the original livestream. Select a time to watch that moment. Transcripts are machine-generated with reviewed name and terminology corrections; occasional recognition errors may remain.

7:14:23

Hello

7:14:23

Exciting to be here. My name is Frank. I work at Coatue which is a technology investment firm across public and private markets

7:14:30

So, in our business, what you really need to do is be able to take high conviction bets

7:14:36

on big themes and watch those play out.

7:14:39

I think, honestly, a career is the same way.

7:14:42

And last year when I joined Coatue, the bet that I wanted to make was I think that agents

7:14:47

will have an even bigger impact in investing than they did at coding.

7:14:51

I know that's a big statement.

7:14:53

We're all here because of the transformative impact that AI has had in coding.

7:14:57

But I really believe it strongly.

7:14:59

And today I want to talk a little bit about the framework that we use to actually realize

7:15:03

that impact.

7:15:05

So, at a high level, you can think about a hedge fund as a function that takes in two

7:15:10

parameters, context external and context internal, and spits out one tuple.

7:15:17

Selection, size, timing.

7:15:20

stock, how much, when.

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And I think this is a good framework to actually ground our work, which is we are trying to

7:15:30

solve this compression problem of how do you take all the information in the world and

7:15:35

spit out this one simple tuple and the product that we provide is essentially a time series

7:15:41

of this tuple that constructs a portfolio.

7:15:44

let's start from the top, which is the inputs.

7:15:48

simple philosophy.

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We use our screens, we look at stuff, we do work.

7:15:53

Every single thing that a human can see in pixels on the screen, an agent in your building

7:15:57

should be able to see via API.

7:15:59

The analogy I use is imagine you brought the smartest people ever, the greatest investors

7:16:05

alive and you brought them into your company but you gave them a computer without logins

7:16:10

to 75% of your services.

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It's almost immaterial how smart this system is if it doesn't have the tools to actually

7:16:17

action that.

7:16:18

So the two parts, external context, no surprises here, think the news, prices, filings, all

7:16:27

of that should be easily accessible and not via dragging and dropping, copy and pasting,

7:16:33

like directly via API.

7:16:36

Internal context is just as important, right?

7:16:40

So this is your own firm situation.

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So that might be our current positions, potential liquidity and risk requirements we have around

7:16:47

certain names, and past case studies or history with a certain sector or stock or management

7:16:55

team.

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That is all super important.

7:16:58

So this is the foundation, and I think, no credit to me, Coatue has been an amazing leader

7:17:03

on this for over a decade.

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It is both technological and cultural.

7:17:07

We have an amazing data science team, amazing processes, amazing systems that bring all

7:17:13

this in, and just as importantly, we have a culture that is super, super rigorous and

7:17:18

built from the ground up to capture all this insight.

7:17:21

For decades, we filed every single note about every single trade, about every single decision

7:17:26

we made or didn't make about what went well and what didn't go well, and that has poised

7:17:30

us to expose us to AI.

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If you think about it, I probably can't just take all of those things, jam them into a

7:17:39

context window and get my magic three numbers and go home.

7:17:44

It can't be that easy.

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You probably have to break down this function a bit further.

7:17:50

So maybe the first step is I take in that external and internal context and I gather

7:17:57

I want to gather it, I want to filter out what is relevant and not relevant.

7:18:01

Okay, well, I pulled some news articles about the MBA that probably isn't material to stocks,

7:18:06

but this is related to local permitting that might impact data centers.

7:18:13

There is a lot of nuance in this gather step.

7:18:17

you will see probably the next step is I need to analyze that information and form

7:18:21

a view.

7:18:22

I need to think about what that means for the markets, public and private, and then

7:18:30

I need to take that view and turn it into a decision.

7:18:33

A decision object has these three parameters, these three sub pieces.

7:18:39

You can see every single step has an input and an output, and the input for the subsequent

7:18:46

step is the output that the previous function generated.

7:18:50

I think as an engineer, this is a way for me to conceptualize the problem in a way that

7:18:56

makes a lot of sense.

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But even this, it really can't be as simple as writing three functions.

7:19:02

So let's just, to really appreciate the scope and understand the full complexity of the

7:19:09

problem, let's look into the first step, a tiny sub piece of a tiny sub piece of just

7:19:15

gathering information and let's do a case study on interpreting the news.

7:19:21

So it's probably no secret to you guys that news from Asia and Korean media outlets has

7:19:29

been super important this year because semis, AI, have been a huge, huge theme in the market.

7:19:35

Huge theme.

7:19:36

And I think this is an area where AI is poised to have a lot of impact.

7:19:41

Reading Korean language news better than our completely non-Korean speaking staff.

7:19:48

I think I have a good thesis that this might be a good use case.

7:19:51

So you can imagine the first step is I have articles.

7:19:57

I need to collect the articles.

7:20:00

could be an MCP, this could be a CLI, license the data feeds, clean the data feeds. There are a lot of ways to do this and a lot of dimensions of freedom for how you can even just write this simple piece. How do I chunk it when I pass it to the LLM? Do I want to pull the images as images? Do I want to pull the images and then turn the images into text? There are actually a lot of knobs here.

7:20:24

I almost think about those knobs as hyperparameters in a traditional machine learning system.

7:20:30

I think about each of these knobs as something for me to tune and optimize against.

7:20:36

Obviously, filtration, we talked about it.

7:20:41

There are probably Korean NBA fans, right?

7:20:42

There is probably a bunch of stuff that is not necessarily material to the names and

7:20:50

themes and stocks in our portfolio that really, really matter.

7:20:53

So I want to make sure that I filter those out.

7:20:58

There is this translate slash extract slash should I summarize, should I extract this

7:21:03

into some sort of structured form.

7:21:06

Again, so, so many ways to do this, so many ways to experiment, how to expose information

7:21:10

to the model, and one of the reasons this is hard is it keeps changing.

7:21:15

And obviously checking.

7:21:17

Checking our own internal notes, our own internal views, potential conversations we have had,

7:21:22

meeting recordings against these things.

7:21:24

We actually need to cross-reference those things.

7:21:28

Actually the idea of pulling information from disparate sources and cross-referencing them,

7:21:32

that's super powerful.

7:21:34

So you will see on the right here I have code, LLM, LLM, code, person.

7:21:39

There's many, many ways to run these functions.

7:21:42

I think about, oh, yeah, and finally, update.

7:21:46

We update our views.

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There are many ways to run these functions.

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I think of each line as having a runner, and the most obvious one is code.

7:21:58

Code is very good.

7:22:00

It is fast, it is cheap, it is reliable, so for something like if the prices to earnings

7:22:07

ratio is less than 15, I should just use deterministic code for that.

7:22:12

Runner number two is statistics, classical machine learning, and you can imagine fitting

7:22:19

the line to a regression for a specific pattern, this is very powerful because you can model

7:22:23

much more complex relationships than just pure deterministic code.

7:22:28

And for even more complex relationships, the reason we are all here, LLMs, AI agents, that's

7:22:34

another type of runner.

7:22:36

So for something like summarization, that's the state of the art.

7:22:40

It's probably totally impossible to build a bunch of if statements that can summarize

7:22:46

better than a modern LLM.

7:22:49

Of course, people.

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People are important runners in the system.

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Imagine a function meeting the management team of a company.

7:22:58

I probably don't want to send an LLM or an AI agent in to do that.

7:23:04

I probably don't want to send an if statement into that meeting.

7:23:07

I think there are many cases where because of judgment and the ability to navigate the

7:23:12

real world and all of these things, a person is the best runner for a given piece of the

7:23:16

function.

7:23:18

I think this is a super, super important point.

7:23:21

There is no glory in automating things for the sake of automating things.

7:23:26

The goal is not to take as many things and make them LLM as possible for us.

7:23:30

The goal is for any given piece of this function, what can I do to maximize absolute quality?

7:23:40

And if you actually think about the function, it probably looks something like this.

7:23:44

It's probably not just a linear statement of a bunch of different things.

7:23:47

There's probably all kinds of branching logic and all kinds of ways to actually fork this.

7:23:52

So maybe I want to collect the information and then translate it, and my main goal is

7:23:56

to extract quotes and check those against sources to make sure that these are actually

7:24:00

the things that people said, and that's my approach.

7:24:03

But that might be totally wrong.

7:24:04

Maybe what I want to do is I want to de-dupe and then I want to filter and then I want

7:24:09

to pull external figures or maybe I want to do something totally different.

7:24:13

I actually want to, I'm passing in a note first and I want to find other confirmatory

7:24:17

data points or maybe I'm trying to red team.

7:24:20

There's a million different ways to configure this.

7:24:22

So yet again, more hyperparameters within the control flow, right?

7:24:29

So many ways to think about just this very simple problem of pulling, filtering, summarizing

7:24:34

aggregating the news for LLMs.

7:24:38

And each of these boxes probably has an optimal runner, right?

7:24:45

So the optimal runner might be deterministic code for collection, right?

7:24:51

I'm pulling last 24 hours for a given source.

7:24:55

That's deterministic code.

7:24:57

Filtration?

7:25:00

models maybe.

7:25:01

LLMs?

7:25:02

statistical methods, a combination, right?

7:25:06

So this probably understates the complexity.

7:25:08

The reality is most things are multi-runner.

7:25:10

Most things have deterministic code plus LLM plus statistical method or human with LLM

7:25:15

in conjunction.

7:25:18

reality is it's probably combinatorics between my four buckets and there's even more

7:25:23

buckets than that.

7:25:24

Because within the LLM category I can tune the model.

7:25:28

I can choose big model, small model, medium model.

7:25:31

I can tune thinking effort. X high, high, medium, I can tune harness. I can choose the harness. I can

7:25:38

choose which skills load with the harness. I can choose which hooks load with the skills.

7:25:41

So yet again, more hyperparameters within my search space. I have an absolutely enormous

7:25:46

amount of hyperparameters within my search space. And this is just for this one tiny problem, right,

7:25:51

of just filtering the news. So the way to think about breaking down these problems is what can I

7:25:58

actually compartmentalize in a way that we can understand and evaluate.

7:26:03

That's what I'm hill climbing against.

7:26:04

Otherwise I'm just tuning these things.

7:26:06

I'm okay, that should actually be a machine learning system instead of an LLM.

7:26:10

That should be a little model that we train.

7:26:12

Oh, no, that shouldn't be a model at all.

7:26:14

That should be an if statement.

7:26:15

Or, oh, man, LLMs are really, really bad at translating that to portfolio impact.

7:26:20

It should really be a human on that step, but they're using a deterministic system to

7:26:25

help them search and pull the information.

7:26:27

It could be all different things.

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And if you don't have a north star to hill climb against, you're just kind of, you're

7:26:34

just fidgeting around.

7:26:35

And I think I cannot convey enough that this is just one tiny thing we do.

7:26:40

Imagine every single data source that we pull in, there's probably more than just three

7:26:45

transformations to get them to the intermediate output.

7:26:47

So the actual graph of Coatue and funds like Coatue, it actually probably looks, oh, not

7:26:54

like this.

7:26:56

is my screen saver.

7:26:58

The actual graph probably looks something like this.

7:27:02

It is probably massively complex.

7:27:04

In each of those nodes, we just talked about at least ten hyperparameters with at least

7:27:10

20 different values for them.

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So the search space is basically infinite.

7:27:15

And figuring out how to actually lay this out in a way that you can comprehend both from

7:27:21

technical perspective, but also absorb culturally, organizationally.

7:27:26

That is the great challenge of applying AI in investing.

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And beyond investing, what we're really talking about is creating a state machine that can

7:27:36

take information from the world and understand it well enough to make coherent decisions.

7:27:41

There's use cases for this far and above, wider than just investment firms, in policy,

7:27:48

in non-profits, in drug discovery, in corporate strategy.

7:27:53

I think one of the most exciting things for me

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about being in forums like this

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is talking to other people in different spaces

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with different problems that kind of congeal

7:28:02

on the same problem space.

7:28:03

I'd love to keep talking about this.

7:28:05

I'll hang out in the hallway afterwards.

7:28:06

Here are my socials.

7:28:08

And thank you, everyone, for your time.

7:28:10

Thank you.