Saudi Arabia-based Advanced Energy Systems (ADES) has become the world’s largest offshore drilling rig manager, with 77 units under management by mid-2026, according to an analysis by Westwood Global Energy Group published on July 23.
ADES moved into the top position after expanding its fleet through acquisitions and new agreements, overtaking China Oilfield Services Ltd. (COSL), which currently manages 66 offshore drilling units.
The company’s growth was driven largely by its acquisition of Shelf Drilling, completed in November 2025.
“Shelf added 33 units to ADES’s portfolio and increased its international presence. At the end of 2024, only six of ADES’s jackups were outside the Middle East. As of mid-2026, ADES now has 33 units in regions beyond the Middle East, making it truly an international contractor,” the report stated.
Westwood noted that ADES’s rise comes as the global offshore drilling market experiences greater consolidation. While the total offshore rig fleet declined from 717 units at the end of 2024 to 693 units by mid-2026, the 10 largest offshore rig managers increased their share of the market, controlling 50.9% of the global fleet compared with 50.6% during the previous review.
Other major drilling contractors have also seen changes in their rankings. Valaris, which ranked second at the end of 2024 with 47 managed units, moved to third place with 37 units following fleet adjustments ahead of its planned merger with Transocean.
Transocean announced in February 2026 that it agreed to acquire Valaris in an all-stock transaction valued at $5.8 billion. If completed without additional fleet changes, the combined company would manage 64 offshore drilling units, according to Westwood.
While contractors continue to expand through acquisitions, new offshore rig supply remains limited. Westwood reported that only 26 rigs are currently under construction globally, including 13 jackups, seven semisubmersibles and six drillships, with many ordered more than a decade ago.
“Much of the technology and software is now out-of-date or no longer preferred, which would increase the time and cost to prepare the units for final delivery. It is highly likely that several of these undelivered units will never see the light of day as drilling rigs. Some may be converted for other uses, and some may be cannibalized for steel and other parts,” the analysis explained.
Regional concentration remains strongest in the Gulf Coast of the United States, where the 10 largest rig managers control 94.4% of the offshore fleet. West Africa has also seen increased concentration, with major managers controlling 68% of rigs in the region.
Westwood noted that Latin America remains less concentrated among the largest offshore contractors, with countries such as Brazil and Mexico continuing to rely heavily on local drilling companies.
