The US Department of Justice (DOJ) has recommended that Google, a subsidiary of Alphabet, divest its AdX advertising marketplace and DFP ad server.

This proposal follows a federal judge’s ruling that found Google unlawfully dominated two online ad-tech markets, said in a court filing on May 5, 2025.

A trial is scheduled for September to discuss potential remedies for Google’s dominance in ad tools used by online publishers.

The DOJ claims that divestitures are essential to dismantle Google’s monopolies and restore competition in the ad-exchange and publisher ad-server markets.

🔗 Source: Reuters

🧠 Food for thought

1️⃣ The Google ad tech case marks a historic shift in US antitrust enforcement

The DOJ’s push for Google to divest AdX and DFP represents a dramatic departure from decades of more cautious US antitrust enforcement, which typically favored behavioral remedies over structural ones.

This case follows a series of European actions, including a €1.49 billion fine in 2019 for Google’s abusive practices in online advertising through its AdSense program 1.

The judge’s ruling confirming Google’s illegal monopolies in both publisher ad servers and ad exchanges suggests US regulators are now willing to pursue remedies once reserved primarily for European regulators 2.

This reflects a broader bipartisan shift in US antitrust philosophy, with both Republican and Democratic state attorneys general joining forces in investigations against Google’s business practices 3.

The DOJ’s stance aligns with a growing academic and regulatory consensus that behavioral remedies alone have proven insufficient to address entrenched monopoly power in digital markets.

2️⃣ The bundling of ad tech products created a self-reinforcing monopoly

Judge Leonie Brinkema’s decision specifically highlighted Google’s bundling of its ad server (DFP) and exchange (AdX) as a key mechanism for maintaining its monopoly position 4.

This finding confirms what publishers have long suspected: that Google’s integration of these products created a system where using one product effectively required using the other, making it nearly impossible for competitors to gain market share 5.

Google’s ad tech dominance grew from a series of strategic acquisitions, most notably its $3.1 billion purchase of DoubleClick in 2008, which gave it control of the publisher ad server that would become the industry standard 4.