ON Semiconductor, the Phoenix-based chip maker that has been trying to buy rival Fairchild since November, completed its $2.4 billion acquisition Monday.

The deal includes the Fairchild plant and offices in South Portland, where about 650 people are employed making the building blocks for digital circuitry. ON’s statement about the acquisition did not say how Fairchild’s existing plants would be affected, if at all.

However, it did promise aggressive cost savings in the future, a strategy that analysts said could include closing plants.

“The acquisition of Fairchild is a transformative step in our quest to become the premier supplier of power management and analog semiconductor solutions for a wide range of applications and end-markets,” ON President and CEO Keith Jackson said in the release. “Fairchild provides us a platform to aggressively expand our profitability in a highly fragmented industry. With the addition of Fairchild, our industry-leading cost structure has further improved in a significant manner and we are now well-positioned to generate substantial shareholder value as we integrate operations of the two companies.”

ON expects to achieve annual cost savings of $160 million by the end of 2017, $200 million by the end of 2018, and $225 million by the end of 2019. Those targets are based on Fairchild’s 2015 annual results.

CONSOLIDATION, POTENTIAL LAYOFFS

Speaking in a conference call Monday afternoon, ON executives did not discuss specifics about layoffs or facility closures among the company’s combined manufacturing operations. They said they do expect some consolidation to occur, but not until 2018.

“There is room for savings from consolidation of the facilities,” said ON Executive Vice President and Chief Financial Officer Bernard Gutmann.

Neither ON nor Fairchild responded to requests for comment about the plans for the South Portland operation.

Analysts agreed that consolidating chip fabrication plants, or fabs, is one way the combined company could reduce costs and achieve higher profits.

“I think the R&D (research and development) and sales/marketing cost reductions are more easily attainable and those represent the large bulk of the forecasted synergies from the Fairchild deal,” Seeking Alpha analyst Stephen Simpson wrote Thursday.

ON had been waiting for regulatory approval from China for the acquisition, which came late Friday. It received approval from U.S. regulators three weeks ago.

Fairchild employees approached by a reporter Monday declined to comment on the deal.

Fairchild, which was headquartered in South Portland until it moved to San Jose, California, in 2011, makes semiconductors that control the power supplies in electronic devices, automobile components, industrial equipment and electronic signal converters. ON Semiconductor also makes power supply chips, along with semiconductors for mobile phones, lighting, medical and consumer applications.

ON has said that it sees growth opportunities in the automotive market, based on the increasing complexity and sophistication of electronic systems in vehicles, as well as in smartphones and computers.

Even so, Simpson said cost savings is where the real value of the Fairchild deal lies. He said it is “at least plausible” that the combined company can achieve the savings it is predicting, but he criticized ON for squandering opportunities to consolidate and streamline in past acquisitions.

“The big question for investors isn’t whether they can do this, but whether they will, and the answer there is harder to determine,” he said. “ON’s track record with deal-driven synergy isn’t good.”

SURGE OF CHIP MAKER MERGERS

Deals involving chip makers have become much more frequent lately because the costs to design chips have increased while sales have slowed. Buying companies that already make chips and have a piece of the market, instead of investing in new designs and building new plants, is seen as the preferred way for a company to expand. Dealogic, a financial analysis firm, identified $104 billion in chip company acquisitions in 2015 alone, compared with $38 billion in 2014.

In 2011, ON acquired Sanyo Semiconductor for $600 million – the first time a Japanese semiconductor company was bought by a U.S. company. In 2014, it purchased Aptina Imaging for $400 million and Tennessee Imaging Inc. for $92 million to expand its presence in the image sensor market.

Gartner Inc. semiconductor analyst Stephen Ohr told the Portland Press Herald in November that the South Portland fabrication plant is older than most of those owned by ON, which places it at greater risk of closure. If the chip market continues to contract, he said, company officials would be more likely to close an older plant.

Ohr also said that Fairchild is not seen as much of an innovator in the market, further complicating the positions of its products and people in the combined company.

KEY SOUTH PORTLAND EMPLOYER

Despite the relocation of its headquarters five years ago, Fairchild still has some corporate offices on Running Hill Road in South Portland, a short distance from its chip-making plant on Western Avenue. Between the two locations, Fairchild has about 650 employees, making it South Portland’s seventh-largest employer, according to city data.

The all-cash purchase by ON values Fairchild stock at $20 a share. Fairchild’s stock closed Friday – its final day of trading – at $19.86 a share.

Fairchild announced in September that it had hired Goldman Sachs to help it find a buyer. At the time, ON was identified as a likely purchaser. Infineon Technologies, a German chip maker, also was named as a potential buyer.

A Chinese group led by China Resources Holdings Co. and Hua Capital Management made a higher offer of $2.46 billion, or $21.70 a share, but the proposed deal was rejected because of regulatory concerns.