U.S. antitrust laws prevent a formal deal and there is no suggestion the two sides would coordinate on production decisions. But the Texas regulator is considering curtailing output in America’s largest oil-producing state for the first time in decades, people familiar with the matter have previously said. Related Mr. Sitton said he would gauge international reaction to the idea of production cuts before deciding how to proceed. “I’m not advocating for Texas to do anything on its own,” he said in an interview. Meanwhile, Wayne Christian, the Texas commission’s chairman, said he has a number of reservations about a production curtailment. Shale-oil companies, which are heavily in debt and produce at a higher break-even price compared with conventional Russia and Saudi producers, have been hit hard by the slump. That has led in recent days to stepped-up U.S. engagement with OPEC—which President Trump has often accused of anticompetitive behavior. […]