The talks between Warburg Pincus and Fusion Microfinance had commenced as early as March this year. : Global private equity player Warburg Pincus has made a debut investment in the Indian microfinance (MFI) space as it announced on Tuesday that its affiliate has acquired a significant minority stake in Fusion Microfinance, a New Delhi-based non-banking finance company-MFI, by leading a Series-E investment round worth Rs 520 crore. The investment round includes both a primary fund raise and secondary sale by early stage investors. Creation Investment, an existing investor, has also participated in this round.