(Bloomberg) -- Boeing Co. is at risk of losing its investment-grade credit rating as the embattled planemaker faces the prospect of a drawn-out strike by workers that will further disrupt production and cash flow.

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The credit score on Boeing’s unsecured debt has stood at Baa3 with Moody’s Ratings since April. Moody’s said in a statement on Friday that it’s reviewing the ratings for a possible downgrade and that it “will assess the strike’s duration and impact on cash flow and the potential equity capital raising Boeing may undertake to bolster its liquidity.”

Boeing has been fighting to hang on to its investment-grade rating, a mission that’s now been complicated by the strike called by workers overnight. The company has more than $45 billion in net debt and has been bleeding cash after it was forced to pare back output in the wake of a near catastrophic accident in January.

A descent into junk territory would increase Boeing’s borrowing costs at a time when it’s struggling to turn around its commercial and defense operations. Boeing has also been losing money on some defense contracts, and its space business has been dogged by delays and cost overruns. The company has $4 billion of debt coming due in 2025 and also $8 billion coming due in 2026, according to Moody’s.

There are other financial consequences to a junk downgrade, such as a smaller pool of investors willing to buy a company’s debt. Two credit graders must lower a company to speculative grade before its debt leaves the investment-grade index and is no longer considered high grade.

Chief Financial Officer Brian West told analysts at a Morgan Stanley conference on Friday that the company will consider necessary steps to shore up its balance sheet. The planemaker is evaluating its capital structure to ensure it can meet its upcoming debt payment over the next 18 months, he said.

“We remain committed to manage the balance sheet prudently,” West said at a conference. “We want to prioritize the investment grade credit rating.”

About 33,000 workers at Boeing’s main sites in the Seattle area voted last night to reject a new labor accord and go on strike. Boeing has said it’s willing to get back to the negotiating table, after offering a 25% pay increase alongside other sweeteners. It’s unclear how long and disruptive a strike might be, and the union leadership has also said it’s willing to resume talks.