Pioneer Natural Resources Co. announced that CEO Timothy L. Dove, who has been with the company for 24 years, would retire immediately. Chairman Scott D. Sheffield  is again taking the helm. Sheffield, founding CEO who served from 1997-2016, has been chairman since 1999. Lead director J. Kenneth Thompson has been named chairman. Pioneer in its 4Q2018 report said net income fell by more than half year/year to $324 million ($1.89/share) from $665 million ($3.87). Mark-to-market derivatives gains recorded during 4Q2018, excluding one-time items, put adjusted net profits at $202 million ($1.18). “Tim has expressed his desire to retire and we have mutually agreed that now is the right time,” Sheffield said. “Over the last several years, our industry has changed significantly, and we have become a pure-play Permian company...In the coming weeks, I plan to engage with our employees and shareholders to understand their views on how to expand Pioneer’s industry leadership position.”