Nabors Industries Ltd. swung to a second-quarter loss in the contract driller's first full quarter since its business that includes hyrdaulic-fracturing services was combined with C&J Energy Services Ltd.

Under the deal, C&J gained Nabors completion-and-production businesses in the U.S. and Canada, which help companies get their wells ready to pump oil and natural gas. C&J's board and management keeps the reins of the business, though Nabors has voting control of the combined entity with a 53% stake. C&J plans to release its second-quarter results Wednesday.

Nabors said it is recording its share of C&J earnings with a one-quarter lag. As a result, Nabors second-quarter results include a loss of $800,000 related to its stake in C&J during the first quarter.

Chairman and Chief Executive Anthony G. Petrello said Nabors operating results for the second quarter "while down significantly, were better than we had anticipated."

Mr. Petrello said Nabors expects another decline in the third quarter. However, he said added that the company thinks that it may "represent the bottom in most areas outside of the U.S. Lower 48," as international rig startups and fourth-quarter seasonal upticks in Alaska and Canada should "mitigate some of the impact of further pricing erosion in the U.S."

Overall, Nabors reported a loss of $36.8 million, or 13 cents a share, compared with a year-earlier profit of $65.7 million, or 21 cents a share. The latest period included a net gain of 23 cents a share, mostly related to the C&J transaction. The per-share loss from continuing operations was 14 cents.

Revenue slumped 47% to $863.4 million. The year-earlier period included $535 million in revenue from the completion-and-production businesses that is now merged with C&J.

Analysts polled by Thomson Reuters expected a per-share loss of nine cents and revenue of $799 million.

Write to Tess Stynes at tess.stynes@wsj.com

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