(Bloomberg) -- Bonds of Boeing Co. and its supplier Spirit AeroSystems Holdings Inc. slid in secondary trading Monday morning after a fuselage panel blew off a 737 Max 9 aircraft during an Alaska Airlines flight Friday. 

The spread on Boeing’s 5.15% notes due 2030 widened 18 basis points to 113 basis points as of 9:53 a.m. New York time, on track for the biggest one-day increase since Jan. 13, 2023, according to Trace bond trading data. The cost to protect the company’s debt against default for five years in the credit derivatives market jumped 16 basis points to 82 basis points, according to ICE Data Services.

Spirit AeroSystems — which makes the fuselage for the 737 Max — also saw its bonds weaken and was one of the biggest losers in the US high-yield secondary market Monday morning. Its 4.6% note due 2028 fell about 4.6 cents on the dollar to 83 cents, the biggest drop since April. 

“The blowout of an unused emergency-exit door on a Boeing Max-9 and subsequent grounding of the aircraft variant to determine the root cause may pressure the companies bonds in the near term,” Matthew Geudtner, Bloomberg Intelligence credit analyst wrote in a note Monday. “While the incident doesn’t alter our intermediate-term view that spreads can continue tightening toward mid-BBB peers, it’s proof of bondholder event risk and volatility.”

The fuselage section that ripped away from the jet midflight reflects a design feature in use for many years, which may mean there was a manufacturing lapse rather than a design flaw, Bloomberg reported. 

Boeing 737 Blowout Points to Pervasive Flaws: Brooke Sutherland

Boeing has about $52 billion of debt outstanding, according to data compiled by Bloomberg. It holds a BBB- credit rating at S&P Global Ratings and Fitch Ratings, one step above junk status. 

--With assistance from Josyana Joshua.

(Updates with total debt and credit ratings in final paragraph)

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