Cybersecurity startup Wiz has turned down a $23 billion takeover bid from Google’s parent, Alphabet, breaking off what would have been the largest acquisition in the search giant’s history. In an internal memo seen by CNBC, Wiz co-founder Assaf Rappaport said the company would instead pursue an initial public offering.

“Saying no to such humbling offers is tough,” Rappaport said in the memo sent to Wiz employees. Had the acquisition gone ahead, it would have doubled the $12 billion valuation that Wiz announced in May after the company raised $1 billion in private funding. According to the memo, Wiz will now focus on achieving $1 billion in annual recurring revenue alongside the IPO — goals the security firm had set before its talks with Google. Neither Wiz nor Alphabet have officially acknowledged that a deal was being discussed.

Wiz offers cloud-based security solutions for enterprise customers, an attractive target that could have placed Google in a better position to compete with industry leaders Microsoft and Amazon. Antitrust regulators have increasingly fixated on deals made by Big Tech in recent years, however, and according to CNBC, both antitrust and investor concerns were cited as reasons for Wiz abandoning the deal.

The Justice Department has already launched two ongoing antitrust lawsuits against Google over its search engine and digital advertising businesses. Google purchased two cybersecurity firms in 2022 — Siemplify and Mandiant — for $500 million and $5.4 billion, respectively, with the latter company best recognized for uncovering the SolarWinds hack.