This is a list of 11 richest men (no woman made the list) in the country who made their wealth through a variety of industries and sectors.

Methodology: The list focused on citizens of Nigeria, We excluded family fortunes. We also did not include former past military rulers whose true wealth is almost always linked to their activities while in government. Likewise persons whose wealth cannot be ascertained without reference to their political career are not included in this list.

No 1. Aliko Dangote:
Networth: $13.6 billion
Age: 55
Source: Sugar, Flour, Cement

Alhaji Aliko Dangote (born April 10, 1957) is the Chairman of Dangote Group, a conglomerate with interests in sugar, cement manufactruing, food processing and freight. Dangote Group is easily the major supplier of sugar to soft drink companies, breweries, and confectioners in Nigeria and several parts of West Africa. Dangote Group was originally founded in 1977 as a small trading company but under Mr Dangote’s watch has grown into a multi-trillion naira company spanning countries like Benin, Togo and Ghana.

Mr Dangote is Nigeria’s wealthiest stockholder with an investment networth of $12.1 billion which comes mostly from Dangote Cement ($11.5 billion or N1.76 trillion), Dangote Sugar ($574.8 million or N87.95 billion).

More on No 1.- http://nairabrains.com/2012/04/exclusive-list-of-11-richest-nigerians-in-2011-their-net-worth-how-they-got-rich/

No 2. Mike Adenuga:

Networth: $5.3 billion
Age: 59
Source: Telecom, Oil & Gas, Banking

Nicknamed ‘the Guru’ Adenuga is a billionaire with interests in telecom, oil and gas, banking and real estate. He is the Chairman of Globacom, the second national carrier and second largest mobile telecommunications company in Nigeria. His company Globacom recently made forays into several African countries such as Benin, Ghana and Ivory Coast as it seeks to build what it calls Africa’s largest telecommunications network. He recently invested $1 billion in laying a submarine cable connecting Nigeria to the rest of the world.

The Mike Adenuga Group also controls Equitorial Trust Bank, Conoil plc, a petroleum marketing company and Conoil Producing, a crude exploration company.

Not much is known of Adenuga’s business methods and concerns as he has opted not to go public with many of his business interests. Less than a year ago Forbes estimated his networth at about $2 billion but Adenuga is worth more than that in our own estimation.

Described as a reclusive billionaire by Forbes Mike Adenuga is worth in the region of about $5.3 billion with one of his companies Conoil Producing, Nigeria’s oil exploration company, producing an estimated 100,000 barrels per day.

More on No 2 - http://nairabrains.com/2012/04/exclusive-list-of-11-richest-nigerians-in-2011-their-net-worth-how-they-got-rich/2/

No 3. Oba Otudeko

Networth: $2.4 billion
Age: 69
Source: Manufacturing, Investments

Ayoola Oba Otudeko (born August 18, 1943) chairs the board of a number of companies including Honeywell Group of Companies, a Nigerian-based conglomerate and holding company with strong international presence.

Ranked 24th richest man in Africa by Forbes magazine Otudeko’s networth is mostly due to his Honeywell Group, a conglomerate founded in the 1980s that is involved in oil & gas, flour milling, engineering, real estate and marine transportation. The Honeywell Flour unit of the group is publicly traded but revenues for the rest of the group’s interests are not disclosed.

Otudeko also owns a 14% stake in Bharti Airtel’s Nigerian wireless phone operations, a company believed to be worth at least $2 billion. Oba Otudeko owns a controlling stake of Radisson Blu, a luxurious 5-star oceanfront hotel in Victoria Island, Lagos. Otudeko is also the largest individual shareholder in First Bank of Nigeria, one of West Africa’s largest financial institutions....

Check out No 4. and so on - http://nairabrains.com/2012/04/exclusive-list-of-11-richest-nigerians-in-2011-their-net-worth-how-they-got-rich/4/

You mean the richest 'armed-robbers'?