Harmony said yesterday Fairtree had acquired a 5.3979% interest.
The Cape Town-based firm describes itself as an investment manager which manages "alternative and long only" investment portfolios for institutional clients and high net worth individuals, with more than ZAR75 billion (US$5 billion) combined assets under management.
Harmony last week closed a US$200 million (ZAR3.5 billion) placement to acquire AngloGold Ashanti's South African assets, Mponeng mine and Mine Waste Solutions.
The 60.3 million shares being issued represented in aggregate about 11.1% of Harmony's share capital before the placing, and were expected to list today.
The new shares were priced at ZAR57.50, which represented a discount of 5.4% to the closing share price on June 24 and a 3.5% discount to the 30-day VWAP.
Harmony CEO Peter Steenkamp said last week the successful placement was a validation of investors' support for the company's strategy to safely grow quality ounces and increase margins.
"We intend replicating our success in South Africa, with decades of acquiring, operating, and extending the life of mines, and extracting additional value from mining operations," he said at the time.
Harmony shares closed 11.55% higher in South Africa yesterday to ZAR67.02, capitalising it at ZAR40.4 billion (US$2.3 billion).