Helios Investment Partners has just closed the Africa's largest-ever buyout fund at $900m. Carlyle Group became the first big US firm to open South African offices in April. A record 79 Africa-focused vehicles are out on the fund raising trail. But private equity has yet to prove it is the new Promised Land.

Africa's risks are well known: politics can be unpredictable, enforcement of legal rights patchy, and skilled managers in short supply. Markets are fragmented by weak infrastructure. Investors may demand a cost of equity more than double that in developed markets. For private equity, the lack of liquid public markets can make exiting investments difficult, and sizeable investment opportunities are lacking. Africa's economic output still is well below that of Germany. Helios's maximum target investment is $250m.