There is another thread about this that hasn't been updated in a few years and with which some people had disagreements as the information became outdated so I'm starting a new one. As someone who has been actively looking into international business schools, I think a thread like this is very helpful.
I will actively keep this one updated and will take people's feedback into account based on reasoning, volume, etc. I firmly believe that with the volatile nature of rankings, clusters are actually far more helpful than the actual number on a given ranking. The schools aren't in any particular order within each cluster (since that's the whole point). A couple of data points I used for the clusters include the Financial Times ranking and the Forbes ranking, which I think are solid in their methodology for international business schools. I focused more heavily on the salary figures from Forbes 5 years out to cluster the schools since I think that's a good proxy for a school's cluster. For example, Forbes shows us that IMD ($226,000), INSEAD ($209,000), and LBS ($210,000) are the only international B-schools where grads make above $180,000 on average 5 years out, hence the Ultra Elite clustering. IE ($175,000) comes next after a sizeable gap hence the Elite clustering.
This is obviously a little subjective but the point of it is to cluster how these schools are perceived in terms of reputation, prestige, and pedigree.
I didn't include Regional Elites here since I think they might deserve their own thread and are generally pretty obvious within each country.
Ultra EliteLondon Business School (LBS)
INSEAD
IMD
EliteIESE
HEC Paris
Cambridge (Judge)
IE
Oxford (Said)
Near EliteSDA Bocconi
ESADE
Cranfield
Warwick
Ceibs
HKUST
Trans EliteImperial College
Lancaster
City University (Cass)
Mannheim Business School
Rotterdam School of Management
University of Toronto (Rotman)
University of Western Ontario (Ivey)