United Technologies Corp. has announced its intentions to buy aviation communications and electronics supplier Rockwell Collins Inc. for $23 billion in cash and stock. The acquisition, including debt, is valued at $30 billion. The acquisition would be the largest in aerospace history.

UTC Chief Executive Gregory Hayes said, “The combination of Collins with our Aerospace Systems business gives us the scale to both innovate and reduce cost to meet the needs of those customers. It gives us scale to do things that we couldn’t do on our own.” The acquisition would create an aerospace behemoth out of two companies that had total revenue of $62 billion in 2016.

The company has said the deal complements UTC’s current business. A new business unit would be created called Collins Aerospace Systems. The unit would be headed by Rockwell Collins’ current chief executive, Kelly Ortberg. The deal is expected to close by the third quarter of 2018.

The deal is subject to approval by Rockwell Collins shareholders and regulatory approvals. According to analysts, the deal is unlikely to be challenged by antitrust officials since there is little overlap between the companies’ products. UTC’s business focuses on aerostructures, landing systems, propellers and engines, while Rockwell Collins creates flight controls, cockpit displays, seating and aircraft interior systems.

The two companies have said the deal would generate cost savings of at least $500 million by the fourth year. A UTC spokesman declined to comment on whether UTC expected any layoffs to follow. There has been speculation that the purchase would prompt UTC to spin off its Carrier air conditioner or Otis elevator units. Hayes did not rule out such sales in the longer term.

Aerospace giant Boeing said it would take a “hard look” at the acquisition proposed by UTC and use the power granted by its contracts with the companies, and its sway with regulators, “to protect our interests.” The company said in its statement, “Our interests and those of our customers, employees, other suppliers and shareholders are in ensuring the long-term health and competitiveness of the aerospace industry supply chain.”

UTC also announced its decision to halt share buybacks for three to four years. UTC shares were down 5.2 percent to $111.82 after its announcements and Boeings comments were made public. Rockwell’s shares rose 0.3 percent in afternoon trading.

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