WALL Street Journal has cited anonymous reports that private-equity firm Apollo is planning a $US15 billion IPO next year after buying the company in 2016 for $7 billion.

Reuters said it would be the largest private equity-backed initial public offering since Hilton Worldwide Holdings went public at $19.7 billion in 2013.

ADT has 20,000 staff across nearly 300 locations and serves 7 million customers, with 2 million connected through the ADT Pulse app. The blue sky valuation of this IPO certainly suggests the cloud-based business model now has serious commercial traction. ♦