By midmorning, the nano-cap had soared 67.1% to $2.49.
Tullow Guinea Limited provided notice to the Government of Guinea that it had lifted its Force Majeure effective from May 3.
"Diligent efforts are being made to satisfy the conditions to resuming petroleum operations which include clarification that the U.S. FCPA investigations of Hyperdynamics will not adversely affect Tullow's operations under the PSC," Hyperdynamics said in a statement.
A force majeure was declared in March due to domestic regulatory investigations into Hyperdynamics. The Justice Department and SEC had been investigating Hyperdynamics' acquisition of exploration rights in Guinea.