AppNexus
| Company type | Subsidiary |
|---|---|
| Industry | Technology, Digital Advertising |
| Predecessor | AppNexus |
| Founder | Brian O'Kelley, Mike Nolet |
| Headquarters | New York City , United States |
Area served | North America, Latin America, Europe, Asia, Australia, Middle East |
Key people | Brian O'Kelley (former CEO), Mike Nolet (co-founder), Michael Rubenstein (former president) |
| Products | Cloud-based software platform for programmatic digital advertising (DSP, SSP, ad serving) |
| Owner | Microsoft (as of December 2021 agreement) |
| Parent | Xandr (AT&T subsidiary until sale to Microsoft) |
Xandr, previously known as AppNexus, is a global American technology company that offers a cloud-based software platform designed to facilitate and enhance programmatic digital advertising. Its headquarters are located in New York City's Flatiron District, and it maintains 23 offices spanning North America, Latin America, Europe, Asia, and Australia.
The company provides technology and infrastructure for online auctions, supporting data management, optimization, financial settlement, and management of directly negotiated ad campaigns. Its comprehensive platform encompasses demand-side (DSP), supply-side (SSP), and ad serving capabilities. Xandr’s system integrates with prominent advertising sources such as Google's "Authorized Buyers" exchange, Magnite, and Pubmatic. It operates numerous data centers globally, including a key facility in Amsterdam that serves the European and Middle Eastern markets.
In June 2018, AT&T acquired AppNexus for around $1.6 billion, incorporating it into its Xandr division as a subsidiary. The division expanded in October 2019 through the acquisition of Clypd, a company focused on programmatic linear TV advertising technology.
By December 2021, AT&T reached an agreement to sell Xandr to Microsoft for an undisclosed amount, subject to regulatory approval.
Founders and financing
AppNexus was established by former employees of Right Media, including CTO Brian O'Kelley and Mike Nolet, who served as product manager and analytics director. Michael Rubenstein, previously a VP and GM at Google’s DoubleClick, joined as president in 2009. The company attracted investment from leading backers such as Microsoft, Khosla Ventures, First Round Capital, Venrock, Kodiak Venture Partners, along with individuals like Marc Andreessen, Ben Horowitz, and Ron Conway. By 2015, total funding reached $250 million. Brian O'Kelley resigned from his CEO position in October 2018.