Moody’s Investors Service has given a thumbs down to Chicago’s plans to expand O’Hare International Airport.

Yesterday, the investment rating agency branded the $8.4 billion project to overhaul O’Hare “credit negative.” Moody’s contends the project will, in part, increase airline costs, “weakening O’Hare’s competitive position and airlines’ profitability.”

The project would add gates, concourses and an updated international terminal at the airport.

O’Hare currently has $7 billion in outstanding general airport revenue and passenger facility charge debt. O’Hare Chief Financial Officer Carole Brown maintains the expansion plan poses no credit risk either to the airport or the city.