Google loses the ad monopoly case, but keeps the monopoly

Once upon a time, the Justice Department’s ad-tech case looked potentially fatal for a significant piece of Google’s revenue. The DOJ wanted a federal judge to force Google to sell its ad exchange, separating parts of a system the court had already found illegally monopolized online advertising markets.

Google lost the case, but kept the business.

U.S. District Judge Leonie Brinkema rejected the government’s proposed breakup Wednesday, choosing behavioral restrictions designed to change how Google operates its ad-tech machinery. This is the second time in roughly a year that a federal judge found Google maintained an illegal monopoly but didn’t dismantle it. 

For marketers, that means the infrastructure underlying much of open-web advertising remains largely intact. The more immediate question is whether the new rules governing that infrastructure create enough competition to affect how inventory is priced, bought, and measured.

Google keeps both sides of the market

The Justice Department sued Google over its ad-tech business in 2023, arguing that the company used its control over multiple parts of the advertising supply chain to suppress competition. Brinkema ruled in April 2025 that Google illegally monopolized the publisher ad-server and ad-exchange markets and illegally tied the two products together. The government failed to prove a separate monopoly in advertiser-side tools.

That distinction matters because Google occupies an unusually powerful position between advertisers and publishers. Its publisher technology manages the inventory offered for sale, while its exchange runs auctions that connect that inventory with advertising demand. 

“The conflicts of interest are so glaring that one Google employee described Google’s ad business as being like ‘if Goldman or Citibank owned the NYSE,’” is how Sen. Mike Lee (R-Utah) described it in 2023.

The Justice Department argued that Google’s ownership of both pieces created a structural conflict that behavioral restrictions could not adequately fix. It wanted Google to divest AdX, its ad exchange, and sought other changes intended to make it easier for competing technology to participate.

Brinkema considered a breakup too difficult and potentially disruptive. During the remedies trial, she questioned who would buy the exchange and how it would operate afterward, suggesting that stopping the illegal behavior could provide a more practical remedy.

The precise terms of the ruling remain partly unclear because Brinkema’s full opinion is temporarily sealed to allow the parties to identify confidential information. The public order says she accepted most of the proposed behavioral remedies, with modifications. 

The auctions should work differently

The changes could still be meaningful for the mechanics of programmatic advertising.

The court previously found Google used practices known as “first look” and “last look” to favor AdX. First look gave Google an early opportunity to buy publisher inventory. Last look gave it information about competing bids before it made its own offer. Google had also imposed pricing rules limiting publishers’ ability to set different minimum prices for different sources of demand. 

Those advantages are being restricted. Publishers will get more pricing control, while competing publisher ad servers are expected to receive Google’s AdX bid information in real time. The goal is to give other ad-tech providers a level playing field to compete for inventory.

For advertisers, the effects will mostly be several layers below the campaign interface. More competition among exchanges and publisher technology could eventually influence auction dynamics, supply paths, pricing, and the amount of advertising money that reaches publishers.

How much changes depends on whether competitors can take advantage of the new rules.

Google still owns the dominant infrastructure. A behavioral remedy can remove some advantages, but it leaves publishers and advertisers operating in the system that sustained Google’s monopoly.

That makes adoption an important measure of whether the ruling works. If publishers begin using competing ad servers or exchanges more frequently, advertisers could eventually gain access to a more competitive supply market. If publishers largely stay where they are, the auction rules will have changed while much of the market structure remains familiar.

Don’t expect ad buying to change overnight

Marketers probably shouldn’t expect their programmatic campaigns to look dramatically different next week.

Open-web advertising growth has already slowed as spending moved toward platforms including YouTube, Instagram, and Amazon, a shift accelerated by Apple’s privacy changes restricting mobile tracking.

That shift also makes the timing of the case significant. The government spent years litigating Google’s dominance of an advertising market that changed considerably while the case proceeded.

The ruling could also make supply-path transparency more important. Marketers may want to look more closely at which exchanges and intermediaries handle their spending, how much of each advertising dollar reaches publishers, and whether alternatives to Google’s stack become more viable as the remedies take effect.

Google survives another breakup threat

This is about more than advertising.

Google also lost the Justice Department’s separate search-monopoly case, in which the government sought structural remedies, including a potential sale of Chrome. In that case, U.S. District Judge Amit Mehta also rejected a breakup, instead imposing requirements involving data sharing and changes in Google’s business practices. 

That leaves marketers with an unusual outcome. The court established that important parts of the advertising market were distorted by illegal monopoly conduct, but the company that built and operates much of that market will continue running it.

The behavioral remedies amount to an experiment: If competitors can use the opening to take a significant amount of business away from Google, then the experiment will be a success. If not, then Google’s monopoly will stand.

It is now up to other businesses to overcome a system in which Google is entrenched among publishers, exchanges, agencies, and advertisers. That’s a big ask, and it will take a long time for it to pay off for anyone who decides to take on one of the world’s largest businesses.

Judge Brinkema decided not to force Google to sell AdExchange because it would have been “potentially disruptive.” But that’s why you do it. Monopolies do not end themselves. The full ruling hasn’t been revealed yet; however, unless there is something really big in it, this remedy seems to be no remedy at all.