The new temporary leader at Harvard University’s endowment will bring a familiar background to the role -- experience in building the Pacific Investment Management Co.

Robert Ettl, chief operating officer at Harvard Management Co., the $37.6 billion endowment’s management arm, is the interim chief executive officer while Stephen Blyth is on medical leave, the Cambridge, Massachusetts-based school said in a statement Monday. The school didn’t specify the medical reason or the length of the leave. Two endowment executives will co-chair the investment committee.

Ettl is the second PIMCO alum leading HMC after Mohamed El-Erian, who was CEO of the Harvard fund from February 2006 to December 2007. El-Erian left Harvard to return to PIMCO as co-chief executive officer. He’s now the chief economic adviser at Allianz SE and a Bloomberg View columnist.

Global Unit

Ettl joined PIMCO in 1995 and helped direct the firm’s international expansion as chief operating officer of its global unit, according to the investment company’s website. He was executive vice president and chief information officer at PIMCO when it was acquired by Allianz. Ettl also held executive positions with Allianz Global Investors, including CEO of the Alpha Vision hedge fund subsidiary.

He previously served in management positions in Salomon Brothers’ government arbitrage trading analytics, technology and operations divisions, according to his bio.

Ettl joined HMC as a managing director and chief operating officer in October 2008. His 2014 compensation package was $4.4 million, up from $4.1 million in 2013, according to Harvard and university tax filings.

Executive Team

“We have a highly experienced executive team at HMC and, together with Bob, they will provide strong leadership in Stephen’s absence,” Paul J. Finnegan, chair of HMC’s board of directors, said in the statement. “We look forward to Stephen’s return to the company, and wish him well as he returns to full health.”

Two Harvard endowment investing executives Rene Canezin, the head of fixed income, credit, and commodities, and Rich Hall, who leads private equity, will serve as co-chairs of the investment committee.

Blyth, 48, has been shaking up the management company since he became CEO in January last year. The senior management team has been overhauled while a number of traders and executives have departed.

Turnaround Plan

A disruption in leadership can be a problem if it comes in the middle of turnaround plan, said Charles Elson, a finance professor at the University of Delaware who runs the John L. Weinberg Center for Corporate Governance.

“A change agent who leaves in the middle of the change dramatically affects the ability to carry out the changes,” Elson said. “If it goes into months or even years the impetus for the change disappears.”

Harvard’s fund had an annualized five-year return of 10.5 percent, trailing peers including Yale University and Princeton University. The endowment’s 5.8 percent one-year gain through June lagged the Ivy League average by 2 percentage points.

Blyth, a former bond trader at Deutsche Bank AG who joined HMC in 2006, was in charge of overseeing internal trading of stocks, bonds and other securities prior to his promotion to CEO. His compensation was $8.3 million as managing director of public markets in 2014, according to Harvard. That’s down from $11.5 million the previous year, university tax documents show.