For the first time in two years, Applied Industrial Technologies, Cleveland, OH, reported sales to customers in the oil and gas sectors increased – and significantly at that, growing 51 percent year-over-year.

The growth was broad-based across its oil and gas customers, AIT President and CEO Neil Schrimsher said during an investor call. "If you think about upstream and upstream in drilling, we saw year-over-year performance in participating sequentially. Also our presence on the production side did well. So, really, in every one of those U.S. plays, a little bit better, but the greatest activity in West Texas in particular that Permian basin."

AIT isn't the only company reporting a return to life for the oil and gas sector. National Oilwell Varco and the distribution company it spun off in 2014, NOW Inc., both highlighted positive movement in that sector in their latest earnings reports.

In April, the U.S. rig count rose to 870, 450 higher than in April 2016, according to the latest numbers from Baker Hughes. But volatility remains a concern for many impacted by the sector.

"I think this level of activity can stay for a period of time and we will know how to operate," Schrimsher said. "Obviously if it gets better, we will do better, and if it gets challenging we know how to operate at that level, as well. Our look forward in the near-term is more at this level, and we will see how the broader economy develops."

NOW Inc.'s global per-rig revenue remained constant in the first quarter, but the U.S. energy segment grew by 26 percent. Revenue pressures remain from a decline in deepwater rigs, even as the number of drilled but uncompleted (DUC) wells continued to rise. The company says it is "walking a tightrope between upstream activity and the need for increased inventory, some with longer lead times."

While sales were down year-over-year for National Oilwell Varco, sequentially the company has reported growth for the past three quarters. "The company is benefiting from two-and-a-half years of intense cost reduction as it capitalizes on the full-fledged recovery underway in North America," noted Clay Williams, NOV president and CEO in an investor call.

"As global oil supply and demand rebalance and oilfield activity grinds higher, NOV is building escape velocity from the black hole the oil industry has been in since late 2014," Williams said. "Oil demand has grown nearly every single year since the first commercial well was drilled in Pennsylvania in 1859, making the oil industry, in my view, the ultimate growth industry for the past 158 years."