Helio Investment Partners has sold half of its stake in Kenya’s largest bank by customers, Equity Bank, to  Norway’s Norfininvest AS for an amount estimated to be more than double its total investment in the east African lenders back in seven years ago.

The Africa focused investment firm that’s based in London said it will sell 12.11 percent of the bank’s shares or 452.9 million shares at unspecified amount. Equity Bank’s shares closed Friday’s trading at 51.50 Kenyan shillings ($0.57), which values Helios stake sale at about $258 million.

The Kenyan Bank has nearly 10 million customer accounts and approximately $4 billion in assets.

Helios bought a 24.45 percent stake in Equity Bank at an estimated $120 million in 2007.

Norfininvest, which was formed two year ago,  is jointly owned by Norfund, the Norwegian Investment Fund for Developing Countries, and Norfinance AS. Norfinance. Is an investment vehicle that targets stakes in banks and financial institutions across Africa.

“Equity is an attractive business with a best-in-class global management team and an established track record within the banking industry,” Kjell Roland, Managing Director of Norfund, said in a statement.

Helios, which aims to return three times its investors’ money, has sought to tap the growing needs of Africa’s emerging middle class, investing in a pan-African billboard advertising agency and consumer banks.

Equity’s high growth on earning and profitability, which has grown more than five folds since Helios invested, has helped the investment firm weather a depreciating Kenyan shilling that has lost nearly a third of its value since 2007.

The London-based PE said during its investment that it would exit the bank in a period of between three and seven years through the Nairobi bourse, but seem to have decide otherwise.

Earlier this week Helios said it had raised over $1.1 billion in one of the largest ever Africa focused private equity fund.