Ross will continue to lead the company's oil group while Chief Operating Officer Gemma Postlethwaite will assume the Chief Executive role.

"She has a keen sense of how clients’ needs are changing and how best to address those needs" Ross said in a statement. "I am now able to focus primarily on making our oil group and its products even stronger."

PIRA was launched in 1976 as a supplier of bottom-up fundamental analysis and is now retained by more than 500 companies in 60 countries including major integrated oil companies, independent producers, refiners and pipeline companies.

"At a time when our clients face very volatile market conditions, we are renewing our commitment to them — the commitment to provide the most expert, objective and integrated analysis of worldwide energy markets," Postlethwaite said in the statement. She joined the firm in 2014.

(Reporting By Jessica Resnick-Ault; Editing by Diane Craft)