When you're walking around Luanda, the capital of Angola, it is hard not to bump into at least one of Isabel dos Santos' investments. The oldest daughter of the Angolan president, Jose Eduardo dos Santos, and Africa's richest woman, she has built a vast empire in one of the world's most expensive cities. Her businesses range from telecommunications to banks to satellite TV to sports. In all, she owns a large chunk of Luanda's major businesses.

Dos Santos controls Unitel, Angola's largest cell phone company, with 81 stores in the capital alone and over 10 million clients in the country. She owns Candando, the country's first supermarket and has stakes in BIC and BFA banks and in the cement company Nova Cimangola. She heads Angola's state-owned oil giant Sonangol as well as the company-sponsored football club, Petro de Luanda. The list goes on and on. She is estimated to be worth $3.2 million (2.9 million euros).

"We could talk about the health sector as well and her connections to the country's big clinics, not to mention diamond businesses," said Angolan opposition member Nelito Ekuikui.

Merit or privilege? 

Some see Isabel dos Santos as a positive example of African entrepreneurship, providing Angola with much-needed jobs in a country with a 24 percent unemployment rate, according to a 2014 census. Youth unemployment is even higher. Other Angolans, like Nelito Ekuikui, do not look at it that way.

"The dos Santos empire in Luanda is a monopoly," he said. "And that's bad for the country because it is more difficult for other entrepreneurs to penetrate the market. If we had new entrepreneurs, we would have more jobs," he added.

Angolan activist Benedito Jeremias thinks that being the president's daughter made it easier for Isabel dos Santos in comparison with other investors.

"Everything she has comes from her father's favoritism and privileges. It is not based on merit," he told DW.

Angolan journalist Rafael Marques has been investigating the origins of Isabel dos Santos' fortune for many years. He said that her father, Jose Eduardo dos Santos, played a crucial role in the construction of her empire.

Everything Isabel wants, her father makes possible, he told DW's Portuguese for Africa service earlier this year. "Her interest in Luanda, as in other [businesses] related to the Angolan state, is to find easy ways to give her financial responsibility over big contracts through presidential decrees", Marques said.

He believes that Isabel's businesses give the president a means to extract money from the country. She has seven half siblings but it is unclear whether or not they share in the profit from the businesses as animosity amongst the family members has been well documented.

Isabel dos Santos has several times denied accusations of favoritism.

What's her next move?

Opposition member Nelito Ekuikui thinks the 43-year-old businesswoman might now be looking for a new challenge. "Sonangol is Angola's biggest company. After heading Sonangol, where will she go?"

Her reach even extends to Portugal, Angola's former colonial ruler, where she is a major investor in the energy, financial and telecommunications sectors.

There isn't much left for her to do in business, Ekuikui says, so "she might give politics a try."

Activist Benedito Jeremias agrees, predicting that the daughter of the Angolan president might even be planning a future as her father's successor.

"I believe she may already be giving orders backstage. The only thing left for her is to become president," Jeremias said.

However, on Wednesday, Reuters news agency reported that Angola's Supreme Court had asked President dos Santos to respond to an enquiry as to why he appointed his daughter head of the state oil firm Sonangol in June this year. The request was in response to a case filed by 14 Angolan lawyers who accuse the president of nepotism and abusing the country's probity laws.

It seems that, for some Angolans, Isabel's seemingly unstoppable acquisition of power has gone on for long enough.