The data centres going up for AI are now so expensive that insurers will not cover one in full. Five years ago the average data centre an insurer was asked to cover was worth about $150 million. Today it is about $3 billion. What insurers will put on a single site has not kept pace, and plenty of these projects now carry cover for a third to a half of what they cost. A fire or a storm rarely destroys a whole campus, so they cover what one bad event could plausibly take out instead of the full cost of everything on site. That is how a $3 billion building ends up insured for a third to a half of what it cost. Count everything at risk on one campus – the building, the machines inside it, the tenants – and it can pass $50 billion. Insurers are in the business of writing risk, so when they start limiting how much they will take on a single site it is worth asking why. The answer is concentration: that much value, in one place, on one grid, inside one weather system. If you are picking the site for the next one, it looks like the cheapest risk management available is not putting it next to the last one.