(Reuters) - Pimco said on Friday Paul McCulley had stepped down as chief economist and as a managing director, a role he had assumed in May at the request of Bill Gross, who was the investment firm's chief investment officer at the time.

The move comes just 10 days after Pacific Investment Management Co hired former Morgan Stanley chief economist Joachim Fels as its "global economic adviser" and a managing director, an appointment that raised questions about McCulley's role at the Newport Beach, California-based firm, a unit of German insurer Allianz SE.

McCulley's last day at the firm will be Feb. 28.

In a statement on Friday, Daniel Ivascyn, Pimco's group chief investment officer, said: "Paul returned to Pimco last May after being recruited by Bill Gross, with whom he had a close friendship and association for more than 20 years. We understand and respect Paul's decision to step down. He is a great friend of our firm and our people, and we wish him great happiness going forward."

McCulley said in the statement he had accepted the position of chief economist at Pimco, a newly created role when he was rehired, "to work side-by-side with Bill Gross, as economic counselor, doing the three things that I love: think, write and speak macro. My mission here is complete."

"I will continue doing the things I love in other spaces, possibly in the academic arena," McCulley said. "Pimco will always be Camelot in my heart."

Mark Grant, managing director at Southwest Securities, told Reuters: "Paul is not only a good friend of mine but he is certainly one of the most experienced and brightest on Wall Street. For him to leave any institution would be a negative for that institution for whatever reason it was."

Pimco had $1.68 trillion in assets under management as of Dec. 31.

(Editing by Bernadette Baum)