U.S. energy sector activity maintained its strong momentum in third quarter 2018, according to executives responding to the Federal Reserve Bank of Dallas Energy Survey. However, respondents said pipeline constraints, steel tariffs and oil price differentials could have negative effects on their business.

The business activity index dipped very slightly from 44.5 in the second quarter to 43.3 in the third but remained near the highest level since the survey began. The business activity index for oilfield services firms fell from 54.2 to 45.9, suggesting a slight deceleration in growth for those firms. Meanwhile, the business activity index for exploration and production (E&P) firms rose from 37.2 to 41.8.