Rockhopper Exploration plc said it had raised US$3.4 million (£2.8m) from an open offer in respect of 39,652,160 units.
The number represents more than 69% of the 57,310,264 available open offer units.
In addition to the placing and subscription on 15 June, Rockhopper has now raised in aggregate US$10.4 million (£8.5 million).