BBC said in a statement that it wished Mahanyele-Dabengwa well and she had the requisite set of skills, qualifications and experience to steer Naspers forward.
She will report directly to Naspers chief executive Bob van Dijk. Sigma Capital is a privately held, majority owned investment group based in South Africa.
Her appointment comes as Naspers gears up to obtain shareholder approval next month to list all its major e-commerce businesses, including its stake in China internet giant Tencent, in Amsterdam, which will essentially leave only Media24 and online shopping company takealot.com in South Africa.
She would lead the day-to-day business in South Africa, a statement said yesterday, and she would also be responsible for its recently announced new units, Naspers Foundry and Naspers Labs, which aim to stimulate the local tech sector and tackle youth unemployment, respectively.
Naspers Foundry is a R1.4 billion investment commitment targeting technology start-ups in South Africa that seek to address big societal needs.
Naspers Labs is a pilot youth development programme to which Naspers had allocated R50million this year and which aims to develop four pilot labs by the end of the financial year, with plans to scale up the operation further thereafter.
Mahanyela-Dabengwa is also a former chief executive of Shanduka Group, an investment holding company she joined in 2004 and left in 2015.
Prior to that, she headed project finance at the Development Bank of Southern Africa.
She was a vice-president at Fieldstone, an international firm that does financing of infrastructure assets before that - she joined them in New York in 1997 and later transferred to the South African office.
She has received numerous awards and The Wall Street Journal once counted her among one of the “Top 50 women in the world to watch”.
Mahanyele-Dabengwa was also selected as a Global Young Leader in 2007 by the World Economic Forum.