The U.K.-based engineer's board had agreed to talks with Apollo after its latest $2.1-billion purchase offer made in April, but neither company would say why discussions ended on an official deal.

The global professional services firm says the deal advances its strategy for environmental consultjng services to account for one-third of its global annual net revenue by 2024.

Funds will go for Nigerian infrastructure projects.

The case centers on activities of subsidiary Amec Foster Wheeler several years before Wood acquired it in 2017.