Halliburton Co. (NYSE: HAL) said it cut more than 6,000 jobs in the first quarter, during which revenue slumped 40.4% and it took a $2.1 billion restructuring charge mainly for severance costs and asset write-offs amid the prolonged slump in oil prices.

Halliburton also postponed its earnings conference call to May 3 from April 25 to accommodate the April 30 deadline to close its acquisition of Baker Hughes Inc. (NYSE: BHI), the company said in a statement after the U.S. market closed on April 22.

The number two oilfield services provider is scheduled to report first-quarter results on April 25. Baker Hughes is due to report on April 27, but has not held conference calls since the merger was announced in 2014.

While the deal will help Halliburton narrow the gap with market leader Schlumberger Ltd. (NYSE: SLB), it faces stiff regulatory hurdles.

The U.S. Justice Department filed a lawsuit this month to block the deal. European Union antitrust regulators could make its objections to the deal known to Halliburton next week, Reuters reported on April 20.

The merger was in part to help weather the oil price downturn that started in mid-2014, and its aftermath. Since 2014, Halliburton has reduced its headcount by about a third and slashed costs as its clients sharply reduce activity.

"Life has changed in the energy industry," CEO Dave Lesar said. President Jeff Miller said, "My definition of an unsustainable market is one where all service companies are losing money in North America, which is where we are now."

The company's first-quarter revenue dropped to $4.2 billion from $7.05 billion. Miller said Halliburton's margins have been resilient, with "decremental margins of only 22% for the quarter."

Schlumberger on April 21 reported negative margins for North America for the first time since the oil slump started. Margins become negative when costs exceed revenue earned.

Halliburton said it expects spending on drilling and completion services to fall 50% in North America this year, following a 40% decline last year. It expects global spending to drop 30% for the second straight year.

U.S. energy firms cut oil rigs this week to the lowest level since November 2009, Baker Hughes said.

Halliburton said it expects that the second quarter will mark the "landing point" for rig count. The company said it typically sees margins improving at least a one quarter after rig count flattens.

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