Mark Wiseman is stepping down as Canada Pension Plan Investment Board's (CPPIB) chief executive after less than four years on the job, spurring a sudden leadership change at the top of a fund that manages $278.9 billion on behalf of Canadians.

The board confirmed the appointment of Mark Machin - currently CPPIB's senior managing director and head of international - as Wiseman's successor on Thursday. Machin is expected to assume president and CEO duties effective June 13.

Wiseman, 46, has worked at CPPIB for 11 years and took over as president and CEO in July 2012. He will become head of the global active equity business at BlackRock, a major U.S. investment firm, beginning in September.

“It was a very, very difficult decision,” Wiseman said in a phone interview with BNN. “It’s a fantastic opportunity as you can well imagine.

“Additionally, [CPPIB] is in spectacular shape. We have an incredibly deep bench, a great leadership team. And that is exemplified by Mark Machin…Frankly, I knew in leaving that the organization was going to be in absolutely fantastic hands.”

Wiseman added that compensation was not a factor in his decision.

Compared with his predecessor, former CPPIB chief David Denison, Wiseman gave the pension fund much less time to develop a succession plan.

Wiseman said that he advised the pension fund’s board “early in the calendar year” and “very shortly after my conversations with BlackRock became material.”

Denison, by comparison, notified the board nearly three years in advance of his departure – informing the board in mid-2009 that he wanted to retire in 2012.

The circumstances of the two former CPPIB chiefs were different, Wiseman said.

“My circumstances, I think I’m a young 46… [Denison] knew he was going to leave when his 60th birthday arrived,” he said. “To be very clear, I don’t think anybody expected, nor were we planning for the fact that I was going to be here for another 14 years to my 60th birthday.”

Wiseman also said the succession planning process began the day he took over as CEO.

“We’ve been developing people, we’ve been reviewing our people with the board from day one, and all we did earlier this calendar year was start to put all that pre-planning just into the process in the normal course,” he said.

Machin, who joined CPPIB in 2012 after working at Goldman Sachs for 20 years and spearheading its Asia operations, was appointed via a unanimous board decision, according to Heather Munroe-Blum, chairperson of CPPIB’s board of directors.

“It is a remarkable honour to have been selected by the Board of Directors to lead this outstanding institution,” said Machin. “I am mindful of the fact that Canadians trust CPPIB with their money, and are counting on us to help ensure that it’s there for them in retirement. This is a major responsibility, one that I assume with respect and great commitment.”

CPPIB says that Machin’s appointment comes at a time when 81 per cent of the fund’s assets are invested outside Canada, yet the fund wants its stakeholders to know this country isn’t being neglected.

“It is likely in the foreseeable future that the CPP Fund will remain overweight in Canada, which represents less than 3 per cent of the global economy,” Munroe-Blum said. “There are approximately $53 billion worth of Canadian investments in the portfolio.”

Under Wiseman's leadership, the CPPIB has grown its head office in Toronto and added offices in other financial centres, including one that opened last year in Mumbai, India.

The CPPIB invests money on behalf of retired and active employees covered by the Canada Pension Plan.

As of March 31, it had $278.9 billion of assets under management, compared with $264.6 billion a year ago. CPPIB on Thursday said it delivered gross investment returns of 3.7 per cent last year despite volatile global equity markets.

Wiseman and his predecessors have taken a non-partisan stance as managers of a body that's designed to operate independently from the federal, provincial or local governments.

Wiseman, who will take the title of senior managing director at BlackRock, also joins the company's global executive committee, a group of about two dozen top executives with broad oversight of the company's day-to-day activities

The role includes oversight of some 350 portfolio managers and other staff responsible for $275 billion in investments. New York-based BlackRock, the world's largest money manager, oversaw US$4.7 trillion as of March 31.

--With files from BNN’s Paige Ellis, The Canadian Press, Reuters