Boeing Co. raised about $21 billion in an expanded stock sale, one of the largest ever by a public company, strengthening its balance sheet as it seeks to avoid a possible downgrade of its rating credit.

The American aircraft manufacturer sold 112.5 million common shares for $143 each, according to a press release. The stock was valued at a discount of about 7.7% to Friday’s closing price of $155.01. Boeing also sold $5 billion worth of depositary shares.

The company’s stock closed down 2.8% at $150.69 on Monday in New York. It has plunged about 42% this year, the second-worst performance on the Dow Jones Industrial Average.

The cash infusion frees one of new CEO Kelly Ortberg’s most pressing tasks at a time of financial crisis for the aircraft maker. Boeing’s balance sheet was already strained by the pandemic, and before that, two deadly plane crashes involving its workhorse 737 Max model. There is now a labor strike, in its seventh week, which is paralyzing airliner manufacturing.

Boeing needed a capital infusion to maintain its investment-grade rating and finance ramping up production of its planes once the walkout ended.

The company is on track to burn through about $4 billion in cash during the fourth quarter, which would bring its cash outflows to about $14 billion for the year. The planemaker hopes to continue spending money throughout the first half of next year as it restarts its factories, including the 737 Max assembly lines.

Boeing factory workers voted last week to reject the company’s latest contract offer, which included a 35 percent pay increase spread over four years. The company plans to reduce its workforce by about 10 percent, Ortberg said in an Oct. 11 memo to employees.

The company received approval on Oct. 23 from the U.S. Securities and Exchange Commission to sell up to $25 billion in stock and debt. Boeing also established a separate new credit agreement worth $10 billion, giving it “additional near-term access to liquidity as we navigate a challenging environment.”

Ortberg is also considering options for streamlining Boeing’s vast portfolio. It has launched a review of its activities which the CEO hopes to conclude by the end of the year. The company is weighing options for the future of its troubled Starliner space capsule program as part of the review, Bloomberg News reported.

The underwriters have the option to sell an additional 16.9 million shares of common stock and $750 million in depositary shares.

Goldman Sachs Group Inc., Bank of America Corp., Citigroup Inc. and JPMorgan Chase & Co. led the capital raise, while Wells Fargo & Co., BNP Paribas SA, Deutsche Bank AG, Mizuho Financial Group Inc. , Morgan Stanley, Royal Bank of Canada and SMBC Nikko also worked on the deal, the release said. PJT Partners Inc. acted as financial advisor to Boeing for these offerings.