It occurs to me that a bubble is sort of unique, it's not just being high in the distribution. A bubble is where some odd factor causes a massive inflation in a

It occurs to me that a bubble is sort of unique, it's not just being high in the distribution. A bubble is where some odd factor causes a massive inflation in an asset that will eventually drop precipitously when there's a correction. What we see with this ratio though is almost the oppsoite. You've just got a fairly reasonable distribution of "bubble risk", it's not like a handful of cities are way out of whack. It's more like there's a sliding scale and naturally some cities are further along it than others. It sort of makes sense that real estate is valued higher in the EU where there are fewer alternative investments that can achieve good returns. Also, I don't really know what the point of having these individual ratings. Surely this is a highly correlated issue? If Frankfurt's prices collapse would you expect Paris to face issues?