jun song park

T2 · manager / operator

Jun Song Park is the founder and CEO of Simile, a company building a foundation model of human behavior for large-scale simulation. Formerly a Stanford researcher leading work on AI agents and simulation (Smallville), he co-founded Simile with Michael Bernstein (ImageNet co-author), Percy Liang (coined 'foundation model'), and Liane (go-to-market).

8 calls·5 names·75% bull·last heard 10 days ago·20VC

track record

no scored calls yet — needs a stated position or a categorical verdict, with a matured window vs SPY

top calls

highest conviction · one per company

1sthigh conviction

$SIMILESimileposition

Simile positions simulation as GPU of intelligence complementing LLM CPU

Park frames frontier LLMs as the 'CPU of intelligence' for rational tasks, while Simile's human behavior foundation model acts as the 'GPU' — massively parallel simulation of diverse human perspectives to capture collective intelligence and emergent social phenomena.

20VC2026-08→

2ndhigh conviction

$GREENOAKSGreenoaks

Greenoaks leads $200M Simile round after deep market preparation

Greenoaks' New Enterprise team had independently researched the simulation market and all players, enabling them to move instantly when Park signaled a round, validating the category's momentum.

20VC2026-08→

3rdhigh conviction

$INDEX-VENTURESIndex Ventures

Index Ventures pre-empts Simile Series B after Shardul calls traction unprecedented

Shardul at Index, having led the prior round, pre-empted the new $200M round after declaring he had never seen this speed of market pull paired with technical progress in his track record of fast-growing markets.

20VC2026-08→

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recurring themes

8 total

$GREENOAKS

Greenoaks

HIGHjun song park·20VC·10 days ago

Greenoaks leads $200M Simile round after deep market preparation

Greenoaks' New Enterprise team had independently researched the simulation market and all players, enabling them to move instantly when Park signaled a round, validating the category's momentum.

"Turns out his team actually has been looking deeply into this market and all the players, how the market is going, and were actually prepared to make the investment, and were look…"

44:45

$INDEX-VENTURES

Index Ventures

HIGHjun song park·20VC·10 days ago

Index Ventures pre-empts Simile Series B after Shardul calls traction unprecedented

"Shardul has sort of this comment that he every once in a while makes where he's seen some of the fastest growing market, and his track record does show that he truly, you know, ha…"

43:44

$OPENAI

OpenAI

MEDjun song park·20VC·10 days ago

OpenAI focused on super-rational intelligence, not human behavior simulation

Park differentiates Simile from OpenAI by noting OpenAI optimizes for super-rational coding, math, and science capabilities, whereas Simile explicitly models human biases, mistakes, and subjective values.

"If you look at large language model companies today, fundamentally the task they have at hand is to create super rational intelligent machines that are good at coding, that are go…"

7:11

$ANTHROPIC

Anthropic

MEDjun song park·20VC·10 days ago

Anthropic grouped with OpenAI as frontier rational intelligence providers

Park lumps Anthropic with OpenAI as companies building super-rational frontier models, contrasting both with Simile's focus on human-fidelity simulation.

"If you look at large language model companies today, fundamentally the task they have at hand is to create super rational intelligent machines that are good at coding, that are go…"

7:11

$SIMILE

Simile

HIGHjun song park·20VC·10 days ago· position

Simile positions simulation as GPU of intelligence complementing LLM CPU

"What I see today that's prominent in AI space is what I consider to be the CPU of intelligence unit. You have these one language model that's really large, that's very smart, that…"

54:19

$SIMILE

Simile

HIGHjun song park·20VC·10 days ago· position

Simile CEO: Defensible data strategy powers human behavior foundation model

Jun Song Park argues AI companies must own a unique, defensible data strategy; Simile combines observational data, RCTs, and A/B testing to build causal models of human behavior that enable counterfactual simulation for enterprise decision-making.

"My fundamental thesis here is for AI companies of this generation, you need to have an interesting data strategy that's going to be defensible. And for us, really the data collect…"

10:04

$SIMILE

Simile

HIGHjun song park·20VC·10 days ago· position

Simile targets $100M simulation sessions for enterprise and government

Park envisions single simulation sessions costing $10-20M to run but delivering $100M+ value by preventing catastrophic decisions, creating a new high-end market for causal simulation at massive scale.

"I think there's a world in which in about 2 3 years, we're running a single simulation session that's going to take 10, 20 million dollars to run a single session, but it's going…"

51:42

$SIMILE

Simile

HIGHjun song park·20VC·10 days ago· position

Simile CEO: Simulation sessions will cost $10-20M but deliver $100M value within 2-3 years

Simile is building a foundation model of human behavior enabling large-scale simulation of populations and markets; the company sees a path to running single simulation sessions costing $10-20M that enterprises will pay $100M for due to prevention of catastrophic decisions, driven by a data flywheel that improves accuracy daily.

"I think there's a world in which in about 2 3 years, we're running a single simulation session that's going to take 10, 20 million dollars to run a single session, but it's going…"

51:40