Private equity fund manager Kerogen Capital has invested US$100 million in convertible preference shares in HKN Holding, a holding company for Iraq-based oil developer HKN Energy. The investment, which was structured through Kerogen Energy Fund will be used for the initial development of an oil project on the Sarsang block in northern Kurdistan, as well as for additional drilling activities. HKN Energy holds a 37 percent participating interest in the Sarsang block and has initiated an option to purchase an additional five percent from the Kurdistan Regional Government.