# Chokepoints in the AI Stack
A chokepoint is a layer where very few suppliers control something everyone else needs, so whoever controls it can restrict the whole system. The concept is about structure, not nationality.
## Current AI chokepoints
- **Lithography.** EUV machines come from a single company, ASML.
- **Leading-edge fabrication and packaging.** Concentrated at TSMC, with advanced packaging a separate bottleneck ([[Advanced Packaging MOC]]).
- **High-bandwidth memory.** A few suppliers.
- **Accelerators and software.** Nvidia hardware plus the CUDA ecosystem ([[Below CUDA - GPU Kernels, PTX and Streaming Multiprocessors]]).
- **Power and grid connection.** Local and slow to expand ([[Grid Interconnection Queues]]).
- **Frontier model access.** Only a few labs can serve the best models, so API access is a potential chokepoint ([[API Distillation]]).
- **Critical materials and refining.** e.g. [[Silver Refining Chokepoint]].
- **Naming and routing.** e.g. [[The Resolver as Sovereignty Chokepoint]].
## Which layers are not chokepoints
Released [[Open Weights]] are the opposite: infinitely copyable, no supplier to pressure. Policy aimed at them after release has little grip. This is why controls end up pushing weight onto hardware, power and access layers.
## The investor question
For any company or policy, ask: which chokepoint does it sit on, does it control one, or is it exposed to one? Durable positions tend to sit on or next to a real chokepoint.
Related: [[AI Chip Export Controls]], [[Jurisdiction and Control Planes]], [[Defensibility Principles MOC]]