One of the reasons that many developing countries such as Mexico have a hard time developing a robust economy and a strong middle class is precisely because their wealth is concentrated in an oligopoly made up of a handful of powerful families who wield vast political and economic power. You'll see this all across Latin America, and in most other parts of the world.

Also, as you can see from the Russian billionaires on the list, many influential people have made vast fortunes when state-owned monopolies were "privatized" and became privately-owned monopolies.

I was going to question whether Mexico is a third world country but I did some googling and yeah, I guess that's an okay assessment. But I think the term "developing country" would be more appropriate.

I think Mexico can be more easily grouped with the BRIC countries, rather than, say, Kenya and Cambodia.

I guess the only point I really want to make is that naming and labeling is a difficult problem, even outside of computer science.

Is it really? Asif Zardari, the president of Pakistan, is estimated to have $1.8 billions. There was a recent uproar in India about some people storing billions in foreign banks etc.

Point is: if you redirect money from where it was intended to be, you can make a lot of money. Especially in 3rd world countries where systems to keep this behavior in check are too weak or non-existent.

(I don't know how Mr.Slim made his money though; I'm commenting more on the surprise for billionaire's from 3rd world countries)