Carlos Slim Helu listing is credited to Mexico and not to any Arab state - he is of lebanese origin. Industry - telecommunications.

There are other Arab billionaires not in the list who have a greater net worth than the number 3 Al Rajhi. I wonder why. I'll list them down as under in order of higher networth

Nasser Al-Kharafi and family Country : Kuwait
Source : M. A. Kharafi & Sons

Naguib Sawiris Country : Egypt
Source : Orascom Telecom Holding

Mohammed Al Amoudi Country : Saudi Arabia/Ehtiopia
Source :Corral Petroleum Holdings

Abdul Aziz Al Ghurair and family Country : United Arab Emirates
Source : MashreqBank

Maan Al-Sanea Country : Saudi Arabia
Source :Saad Group

And then you have your number 3 man in your list
Sulaiman Al Rajhi Country : Saudi Arabia
Source : Al-Rajhi Bank