(Bloomberg) — Boeing Co. is seeking a new $4 billion revolving credit facility from a group of banks, according to people with knowledge of the matter, as it prepares to ride out a potentially lengthy slowdown in global aircraft demand.The planemaker has the option to increase the size of the two-year facility to as much as $6 billion, said the people, asking not to be identified as the transaction is private. So-called “revolver” loans are typically left undrawn by investment-grade rated firms such as Boeing and are used as a back-up form of liquidity.The company has leaned heavily on banks for financing over the past year. In early 2020, following a pair of crashes that grounded its 737 Max airplane, the company signed a $13.8 billion delayed-draw term loan, drawing the full amount down just weeks later amid the onset of the Covid-19 pandemic. That helped kicked off a global dash for cash as corporations tapped banks for hundreds of billions of dollars of financing.Representatives for Boeing and Citigroup Inc., which is leading the deal, declined to comment.Read more: Boeing will draw down $13.8 billion loan to stockpile cashIn recent months, Boeing has faced a raft of suspended or postponed orders as global air travel struggles to bounce back. In addition, the company is now dealing with manufacturing flaws in its 787 Dreamliner, and is trying to resolve issues that have halted deliveries of the jetliner since October.The Chicago-based planemaker’s path to generating cash over the next two years, after burning through $20 billion last year, depends on its ability to offload more than 500 jets — mainly Dreamliners and 737 Max — that have stacked up in inventory.Stockpiling LiquidityBoeing’s new $4 billion revolver is on top of its other existing forms of liquidity. The company already has about $9.5 billion of unused revolving credit facility capacity in three tranches spread out over 364-day, three-year, and five-year portions.While demand for Boeing’s debt has remained strong, the company’s investment-grade rating has come under pressure over the past year. The planemaker is now rated BBB-, the last rung before junk, by both S&P Global Ratings and Fitch Ratings. Moody’s Investors Service rates it one step higher at Baa2.The undrawn fee on the new revolver is 40 basis points based on current rating levels, according to the people with knowledge of the deal. If the company draws the loan, Boeing will pay a spread of 200 basis points over the London interbank offered rate. Boeing must also pay banks an initial 40 basis point upfront fee when the loan is signed.Commitments for the banks that decide to participate are due later this month, they added.(Updates throughout with more information about Boeing’s liquidity.)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2021 Bloomberg L.P.