Michael Sternklar was named COO and head of the Americas at Mercer HR Services, said spokesman Charles G. Salmans. Mr. Sternklar will oversee operations and service delivery, product strategy and development, marketing and communications, and the firms organizational effective practice. He replaces Paul Zurlo, who left the firm to pursue an opportunity in private equity, according to a Mercer news release; no further information was available. Mr. Sternklar served as executive vice president of client services and sales with Fidelity Investments. Fidelity spokeswoman Jenny Engle said Julia McCarthy, who heads the relationship management team, assumed Mr. Sternklars responsibilities on an interim basis while Fidelity executives assess the needs of the team.