Royal Bank of Canada (RBC), the Supply Chain Management Association (SCMA) and Markit Economics released their RBC Canadian manufacturing PMI on Wednesday. The index fell to 52.1 in May from 52.2 in April. It was the highest level since December 2014.

The decline was mainly driven by falls in new business and employment, while output rose to the highest level since June 2015.

"While production and new orders are up, the fall in export sales raises questions about Canada's transition to a more export-led expansion," RBC senior vice-president and chief economist, Craig Wright, said.