The struggling planemaker faces the prospect of a lengthy strike that would crimp production and dwindle cash reserves. 

The credit ratings agency placed all of Boeing's ratings, including its Baa3 senior unsecured and P-3 commercial paper ratings, under review for downgrade hours after the strike was announced by the International Association of Machinists And Aerospace Workers. The strike, triggered by the rejection of a tentative agreement, has halted production at Boeing's Seattle factories. The review will evaluate the strike's impact on cash flow, Boeing's equity capital plans, and production challenges with the 737 and 787 models. 

Moody's noted that prolonged labor disruptions could undermine Boeing's commercial airplanes recovery, complicating liquidity as $12 billion in debt matures through 2026. The strike may lead to a downgrade if Boeing's liquidity deteriorates significantly or if it fails to generate sufficient free cash flow, which remains constrained through 2025 due to production challenges and cost pressures.

Boeing's rating is one step above the speculative grade, which is also known as "junk." The company has emphasized the importance of maintaining its investment-grade rating, showcasing in every quarterly earnings presentations, such as the latest one...