GAC purchased the 80% shareholding from ORO's retiring President Frank H Toftesund. The remaining 20% shares are held by ORO's Managing Director, Ahmet Ozsoy, who will continue to head the new entity GAC-ORO.
"Our partnership with GAC over the past six months has convinced us that closer ties will add strength to ORO's operations and our long-term personal relationships with customers," said Toftesund.
"The continuing leadership of Ahmet Ozsoy will also ensure stability in the new company and ongoing guidance for our staff," he added.
"I am in complete agreement with Frank H Toftesund that there is an ideal fit between GAC and ORO. The compatibility will support the integration of this Norwegian shipping icon with the GAC global network to the benefit of all our customers," said GAC Group President Lars Safverstrom.
The GAC Group claimed that customers would benefit from the link-up with ORO.
"The combination of ORO's Norwegian and North Sea expertise and GAC's global strength in ship agency, logistics and offshore support significantly expands our service offering," said GAC-ORO Managing Director Mr Ozsoy. "This will benefit not only ships calling at Norwegian ports, but also Norwegian vessels sailing to ports around the world."
Established in Bergen, Norway in 1845, ORO has eight offices. Its headquarters are in Mongstad, home to the country's biggest oil, gas and product terminal.