In its release, SNC-Lavalin says Card will become an advisor. The 67-year-old executive said the relationship will continue "through next year," with duties amounting to "whatever Neil and [firm Chairman Lawrence Stevenson] want me to do." Card, an avid fisherman, also will likely pursue that pastime.

Some company analysts had questioned Card's timing as the firm faces bottom-line problems, the pending sale of key toll highway assets in Ontario and legal liability tied to alleged bribery for contracts in its prior regime.

"While Bob Card, in our opinion, did excellent work steering SNC through the toughest period in the company's history, the company has faced execution challenges," said Yuri Lynk, Montreal-based construction sector analyst for Canaccord Genuity in a research note earlier this month.

He said that cost issues "on a handful of projects signed under Mr. Card's watch may have accelerated the transition to Mr. Bruce." Bruce, a veteran executive in mining, power and environmental work who was tapped early by Card in 2013, was elevated to chief operating officer in April.

SNC-Lavalin ranks at No. 12 on ENR's list of The Top 150 Global Design Firms with $2.9 billion in global 2014 engineering and construction revenue. It reported total revenue last year of about $6.1 billion and backlog of about $9.18 billion.

No 'Trigger' For Departure

Card said there was "no single reason" for the timing of his departure. "There is no triggering event that anyone should be worried about and no fundamental change in strategy." Card said he had envisioned a tenure of between three and five years.

Industry sources say that non-Canadians face tax liabilities after a five-year work span.

In the company statement, Stevenson referred to Card's "strong legacy during a critical time for the company with a far-reaching transformation that changed the face of the executive team, repositioned the company strategically ... and turned its ethics and compliance system into a benchmark for the industry."

Card succeeded former CEO Pierre Duhaime who now faces bribery charges linked to a $1.3-billion hospital project in Montreal, along with other executives, and made sweeping changes across its executive ranks to root out past practices and boost its operational performance and tarnished image. He implemented a far-ranging global ethics program and hired as the firm's first chief ethics officer, Andreas Pohlmann, who had helped German conglomerate Siemens out of its bribe-related compliance problems.

SNC-Lavalin also instituted a company-wide "amnesty" program for non-executive employees to gain details of anti-competitive practices, which was a first for a Canadian compahy, the firm said.

"No one questions that our ethics aren't excellent," Card told ENR. "The charges have increased the support for us. People now recognize we are at the top of the industry on ethics."

Even so, the firm's prior activities generated a 10-year debarment from World Bank projects, with some limited exceptions, and nearly cost it the ability to bid for public sector work in Quebec. It eventually won reinstatement in the province but still awaits the result of court proceedings over corruption charges filed by Canada's Royal Canadian Mounted Police in February related to alleged illegal actions by the firm and previous employees in Libya that carry a 10-year federal debarment penalty.