Nigerian philanthropist, fashion designer and oil tycoon Folorunsho Alakija was recently on Forbes‘ list of Africa’s 40 richest people. At number 24, Forbes magazine put her worth at $600 million.

According to Ventures-AfricaForbes may have missed a large amount of Alakija’s wealth when they were calculating. Folorunsho Alakija might be worth over $3.3 billion dollars. That is more than Oprah Winfrey’s fortune of $2.7 billion.

In 1993, Alakija was given an oil block by former head of state General Ibrahim Babangida. Unlike many others that received similar holdings, Alakija chose not to sell. Instead she held on to her rig and partnered, maintaining a 60 percent hold of her oil block, Famfa Oil.

Over the years, Alakija went through a complex maneuvering of buying, selling, transferring and battle for ownership with the former President General Olusegun Obasanjo.

In 2012, the Supreme Court voided General Obasanjo’s acquisition of 50 percent of Famfa Oil which produces 200,000 barrels a day at peak. Folorunsho Alakija’s 60 percent stake in the $10.74 billion company is calculated at $6.44 billion was returned back to her.

Ventures-Africa calculates, assuming debt, if any, Alakija is worth a market value of $3.3 billion.

The editor for Ventures-Africa compares Alakija’s oil field to a similar field, Total E&P.

“Total E&P recently sold off its 20 percent stake in a similar oil field to China’s Sinopec for $2.5 billion,” he wrote. “The oil field in question has a daily production capacity of 180,000 barrels a day. Similarly, other hand, OML 127 in which Famfa has a 60 percent interest produces about 200,000 barrels a day …  At this point, we have no doubt that she is indeed richer than Oprah.”