The article quotes Michael Bloomberg as saying "If we can find a bunch of billionaires around the world to move here, that would be a godsend". But is attracting billionaires to your city a good thing? I can imagine it would be if they paid their taxes and contributed to the local economy, not just themselves but via their companies and personnel. But the article suggests in many cases they don't, i.e. they pay lower taxes and barely visit let alone invest outside the property market.