Territory size is proportional to the combined wealth of all citizens of that territory that are billionaires in 2018.
“The Forbes World’s Billionaires list is a snapshot of wealth using stock prices and exchange rates from February 9, 2018. […] We value a variety of assets, including private companies, real estate, art, yachts and more. We don’t pretend to know each billionaire’s private balance sheet (though some provide it). When documentation isn’t supplied or available, we discount fortunes.” (Quoted from Forbes)
This map uses data by The Forbes World’s Billionaires 2018 Ranking (last accessed May 2018). We aim to map as complete data as possible and therefore estimate data for missing values. In some cases, missing data for very small territories is not used in the cartogram and that area is therefore omitted in the map. Further notes on the data can be found in the downloadable data sheet.