BP faces the challenge as to whether there is sufficient depth across its management team to support its turnaround, RBC Capital Markets analyst Biraj Borkhataria writes after another senior executive departs. Deputy CEO Carol Howle's decision to step down is a "head scratcher" given she was only appointed to the position in April and was put in charge of the portfolio review and long-term strategy, the analysts write. She will be replaced as head of trading by Sam Skerry, who most recently served as head of M&A. BP's M&A track record under Skerry's leadership isn't one to be boasted about but its likely some of the value destructive deals were led by management, he writes. Shares fall 1.4% to 460.70 pence.(adam.whittaker@wsj.com)