Mohamed El-Erian resigned as head of bond-fund manager Pacific Investment Management Co. and will be replaced by Douglas Hodge.

El-Erian, 55, will leave his dual roles of CEO and co-chief investment officer in mid-March, according to a statement today from Allianz SE, the Munich-based parent of Pimco. Bill Gross, co-founder of the Newport Beach, California-based firm, will remain CIO. Portfolio managers Andrew Balls and Daniel Ivascyn will become deputy investment chiefs.

El-Erian has led Pimco’s push to diversify beyond bonds, starting an equity unit and opening products such as exchange-traded funds and hedge funds in anticipation of an end to the three-decade bull market for fixed income. The equity unit faced a setback with the departure last year of Neel Kashkari, hired to lead the stocks push in 2009, to pursue a career in public service.

Pimco’s main fund, Gross’s $237 billion Total Return Fund, had record redemptions last year as clients pulled an estimated $41.1 billion.

El-Erian rejoined Pimco at the end of 2007 after serving for two years as president and CEO of Harvard Management Co. He first joined Pimco in 1999 and was a senior member of its portfolio management and investment strategy group.

He will stay on the international executive committee of Allianz and advise the board of management on global economic and policy issues, reporting directly to Allianz CEO Michael Diekmann, according to the statement.