>>2784497 (PB)
DeBeers was bought out by Oppenheimers in the 19'th centrury. They have controlled the entire dianmond market ever since.
Check out the "overhang" as a possible market weak point. See link below.
http://edwardjayepstein.com/diamond/prologue.htm
Not sure who "the guy who runs all the sugar plantations is, but there is a cuban family now based in Florida that may fit that description.
Perhaps if you know the search engines you could track down this family and see how they've converted FLA to sugar planations and made special tariff and agricultural supsidy deals to produce the dangerous addictive and highly biotoxic sugar you will find them.
https://en.wikipedia.org/wiki/Sugar_industry
After WW II the most profitble contraband substance was saccharine. Black market types used it to make counterfeit sugar which sold for a fortune.
Good luck digging anon, I'm sure you'll come up with something.
Jump in and get started.