Helios – backed by George Soros, Madeleine Albright and Jacob Rothschild – is looking to raise $500 million to invest in the auction.
The company is reportedly in talks with private equity group Providence Equity Partners and a deal could be finalised within the next couple of weeks.
Indian operator Bharti Airtel is aiming to raise $2 billion from the auction, with rivals Helios Towers Africa, IHS and Eaton Towers bidding for different parts of the portfolio.
The sale has been divided into several smaller deals of $500 million.
Africa's MTN Group has also been looking to sell infrastructure in the region. Earlier this month, the operator sold all of its mobile network towers in Rwanda and Zambia to independent infrastructure firm IHS Holding.
