US cybersecurity firm NortonLifeLock has confirmed it is acquiring British rival Avast in order to create a global consumer security powerhouse.

The agreement, which comes just weeks after both companies confirmed they were in advanced discussions regarding a possible combination of the two brands, will see Avast stockholders receive cash and shares that value the deal at $8.1 billion to $8.6 billion. That makes this merger the third-largest cybersecurity acquisition of all time, following Thoma Bravo‘s $12.3 billion takeover of Proofpoint and Broadcom’s $10.7 billion acquisition of Symantec’s enterprise business. 

NortonLifeLock, formed in 2019 as a spin-off from Symantec following the latter, says the deal will create an industry-leading consumer cyber safety business, unlock approximately $280 million of annual gross cost synergies, and dramatically expand its user numbers thanks to Avast’s 435 million-strong customer base.

“With this combination, we can strengthen our cyber safety platform and make it available to more than 500 million users,” NortonLifeLock CEO Vincent Pilette said in a statement. “This transaction is a huge step forward for consumer cyber safety and will ultimately enable us to achieve our vision to protect and empower people to live their digital lives safely.”

Avast, founded in 1988, focuses on cybersecurity software for consumers and small and medium-sized businesses and describes itself as one of the largest security companies. However, the company has not been without controversy during its near-25-year history; Avast was forced to shut down its marketing technology subsidiary Jumpshot last year after it was found to be peddling web browsing data that could be linked to individual users.

Once NortonLifeLock’s acquisition of the company is complete, Pilette will remain CEO of the new business, while Avast CEO Ondrej Vlcek will become president and join the board, the companies said.

“Our talented teams will have better opportunities to innovate and develop enhanced solutions and services, with improved capabilities from access to superior data insights,” Vlcek said. “Through our well-established brands, greater geographic diversification and access to a larger global user base, the combined businesses will be poised to access the significant growth opportunity that exists worldwide.”

The final name of the merged company has yet to be determined, but NortonLifeLock has confirmed it will be dual headquartered in the Czech Republic and Tempe, Arizona, and will seek to cut its number of employees from 5,000 workers to around 4,000 over the next two years. The combined company will be listed on the Nasdaq, rather than Avast’s current London Stock Exchange home.

The deal, which has been confirmed just weeks after NortonLifeLock bought free antivirus provider Avira for £360 million, is expected to close in mid-2022.