Mostly brokers seeking to purchase crude oil allocations.
You buy fresh cut at 52+1, resell at 70 to 75+1.
There are numerous crude brokers in Europe who are willing to pay 75+1 because they flip their crude allocations for cash so quickly anyhow.
You figure..one metric ton of REBCO costs like $540 Million alone. A 60 month contract runs you $32.4B. That's how buy/sell programs for BG's can have such a large turnover.
Especially when countries have been buying and storing lots of crude at lower prices.
As for FORBES list, I know several people not listed. Is Jack Binion listed? He has $1.2 B cash. The Al-Kamali family controls 30% of Saudi Arabia's crude...are they listed? Lahn Tran-Tu? Sheldon Adelson could never sell all his stock and still be worth $15B. Donald Trump? He inflated his worth just for FORBES new listing.