Halliburton and Baker Hughes have called off their $28bn (£19.2bn) merger, which would have represented the largest oil field services acquisition ever.
The deal abandonment comes after the US Department of Justice (DOJ) last month filed a lawsuit to stop the merger.
The DOJ said Halliburton's acquisition of its smaller rival would hamper competition, raise prices and reduce innovation across the industry.
The merger agreement was announced in November 2014.
The deal collapse comes less than a month after Pfizer and Allergan announced the breakdown of their $160bn merger, citing US inversion rule changes.
Following the breakdown of the oil field merger, Halliburton said it will pay Baker Hughes a termination fee of $3.5bn this week.
“While both companies expected the proposed merger to result in compelling benefits to shareholders, customers and other stakeholders, challenges in obtaining remaining regulatory approvals and general industry conditions that severely damaged deal economics led to the conclusion that termination is the best course of action,” said Dave Lesar, chairman and chief executive of Halliburton.
Martin Craighead, chairman and chief executive of Baker Hughes, said: “Today’s outcome is disappointing because of our strong belief in the vast potential of the business combination to deliver benefits for shareholders, customers and both companies’ employees.”