When one supplier holds more than a third of a critical input, the system loses its ability to recover on its own.
Supply chain risk is usually discussed in political terms. It is more usefully understood as a fault tolerance question. When a single supplier controls more than a third of a critical input, the system holding that dependency has no path to self correction if that supplier withdraws.
A single nation controls roughly 98 percent of global gallium supply. Measured against a one third fault tolerance ceiling, that is a concentration nearly three times past the point where the system can recover from a supply interruption on its own.
The framework is simple to state and difficult to implement. No single source above one third of any critical input. Diversification below that line is not an efficiency loss, it is the cost of remaining able to recover.
This analysis treats supply concentration as a static measure. Real supply chains have substitution effects, stockpiles, and recycling streams that a threshold model does not capture. It should be read as a first filter, not a complete risk picture.