⚠ One Site, One Grid, One EventHigh threat

Concentration risk is not theoretical here, and the company's own materials date the precedent.

Kioxia's results presentations have referred to the financial impact of a power outage at the Yokkaichi plant in June 2019¹ — a single interruption at a single site, material enough that it was still being explained to investors years later. Not an earthquake, not a fire: a power cut.

The exposure has grown since. The site now carries six fabs, the company is larger, and flash prices are far higher, so the revenue at risk per day of interruption is a multiple of what it was in 2019.

What partly offsets it is that the same concentration makes recovery faster — engineering resources are on site, and a fault in one building can be diagnosed by people who work in the next one.

The number that matters is not disclosed and would be the most useful figure in the file: revenue per day from Yokkaichi. The observable proxy is the share of output the site carries, which is the majority.