ACS, which runs other toll roads in Canada, said it would retain a minority stake in the project. Its holding now stands at 12.5 percent. It said it had signed a service contract to manage the highway and maintain it.

The Spanish firm did not detail how much it had raised from the sale. It sold its stake to Ontario-based infrastructure firm Connor, Clark & Lunn and Quebec-based pension fund Desjardins.

Canadian mining group Ledcor is also an equity partner in the road project.

(Reporting by Sarah White; Editing by Ros Russell)