Rob Arnott, chairman and CEO of Research Affiliates LLC, has resigned as CEO but will remain chairman, Institutional Investor reported. COO Katy Sherrerd will become the new CEO.

In addition, Arnott will continue to carry out his current research, client, and portfolio management responsibilities, according to the news outlet.

In a statement to the publication, Arnott said Sherrerd had been running day-to-day operations at the company for years.