Are there three or four centibillionaires?

There are now three centibillionaires in the world. Facebook CEO Mark Zuckerberg has breached the $100 billion threshold, to join Bill Gates ($120 billion) and Jeff Bezos ($190 billion), to become only the third person in the exclusive club of those who are worth over $100 billion.
Interestingly, about a year ago, French luxury goods magnate Bernard Arnault was in the news as having achieved membership of the centibillionaire club (along with Gates and Bezos). Does this mean that Arnault has since dropped out of the club? Or is it just that Europeans don't count for some purposes? Or that only tech billionaires count? Or are there actually FOUR members of the club?
Well, it turns out that Arnault WAS actually the richest man in the world (even richer than Bezos), at least for a short time in January 2020. But then the pandemic struck, and Bezos, Gates and Zuckerberg made out like bandits, which Arbault suffered big-time, and by August 2020 his net worth was down to a measly $80.2 billion. So, no longer a centibillionaire.