Customers are craving the conventional and alternative energy technologies proffered by Houston’s NOV Inc., with the backlog sharply higher in the second quarter. However, CEO Clay Williams told investors Wednesday that “continuing supply chain challenges” and rising costs are a concern.

Williams discussed the latest results and what he sees ahead during a wide ranging conference call. NOV’s operating leverage was solid at 50%, in part on cost reductions implemented in previous quarters. 

Those reductions limited the price increases in some product lines, which helped “offset the inflation we are seeing in most product lines,” he said. The pandemic “bankrupted many of our customers,” but the backlog has begun to strengthen, despite “continuing supply chain...