US group HC2 Holdings has put OSV owner Global Marine on the sales block.
It is also exploring other strategic alternatives for the company and its 29-ship fleet.
Deutsche Bank Securities and ABN Amro have been brought in to help with the process.
HC2 acquired Global Marine four years ago.
The group's CEO Philip Falcone said: "They've renewed the fleet of marine assets through strategic acquisitions and re-organised the business to pursue attractive growth opportunities, all while substantially reducing debt that was assumed during the acquisition.
