European Union antitrust regulator resumed its review on Halliburton's acquisition of Baker Hughes. European Comision will decide on the matter by August 11, whether to approve or reject the deal.

Previously US authorities decided to veto the acquisition, deemed it as uncompetitive. Last week, US Justice Department had prepared lawsuit to block acquisition of Baker Hughes. Justice Department remarked the divestation plan Halliburton's assets did not fulfill antitrust law's requirement, so the government prepared to block the deal.

In order to smooth the deal and fulfill the antitrust regulation, Halliburton has offered to divest over $5 billion of its assets. However, the Houston-based company has not made formal offer.

In Europe, the European Commission also expressed similar concern. Reuters reported EU antitrust authority has previously expressed concerns that the deal may reduce competition and innovation. Last month, the European Commission stopped its review for the second time, waiting for more detail information from the companies.

"Once the requested missing information is provided the Commission restarts the clock," Ricardo Cardoso, the spokesman for European Commission spokesman said in an email. According to Upstream, European Commission will now decide by 11 August whether to clear or veto the takeover.

In November 2014, Halliburton acquire Baker Hughes on a $35 billion deal. Both Halliburton and Baker Hughes are the industry leader in the oil field service industry, as the second and third biggest companies. Merger between them will strengthen the company to become second largest oil field service provider, behind Schlumberger which is still the largest in the industry.

USA Today reported that with combined 2015 revenue of $39.3 billion, Halliburton and Baker Hughes control a nearly 16% market share in the oilfield services field, based on IBISWorld data. Both companies provided a wide range of oil services, ranging from oil-well completions, cementing and drilling.

US antitrust authorities and its European counterpart have concern that merger between those two companies will reduce the competition in the oil field service industry. Merger will create a duopoly in the oil field service as Schlumberger and the new Halliburton will be the sole dominant players in the 20 business lines of oil field service company in the world.

Head of US Antitrust Division, the assistant attorney general Bill Baer said that the deal was so anti-competitive that it should never have made it out of the boardroom. He said the merger posed a serious threat to competition and wasn't fixable.

"I have never seen one that poses so many antitrust problems in so many markets," Baer told USA Today. "Our lawsuit should surprise no one."

Meanwhile in Europe, the antitrust regulator continued its investigation on the Halliburton and Baker Hughes deal. The European Commission plan to reach decision by August 11 to whether approve or veto the deal.