Long-time Weatherford International plc Chairman and CEO Bernard J. Duroc-Danner resigned effective on Wednesday. No explanation was offered by the company. The fourth largest oilfield services operator in the world is to be led by interim CEO Krishna Shivram, who also is to continue as CFO until a new financial chief is named. Vice Chairman Robert Rayne is taking over as chairman. The board stated that it was "extremely grateful" to Duroc-Danner for "his leadership, vision, loyalty and the guidance provided to Weatherford and its predecessors for the past 30 years. He has grown and steered the company from humble beginnings into one of the leading oilfield service providers that it is today, providing numerous contributions to both the company and the industry." Shivram, who was appointed CFO in November 2013, previously worked for Schlumberger Ltd.