The Justice Department successfully argued that Google acted as an illegal monopoly . Now comes the tricky part: Deciding what to do about it.

DOJ attorneys are considering a number of options they could propose to US District of Columbia District Court Judge Amit Mehta as early as next month, according to reporting by Bloomberg and the New York Times .

The remedies range from an outright breakup of Google ( GOOG , GOOGL ) to forcing the company to make its search engine data available to competitors to ending agreements that secure its search engine as a default on mobile devices and internet browsers.

The DOJ and Google have until Sept. 4 to propose these or other changes to Mehta, who ruled earlier this month that the tech giant violated antitrust law. A hearing to discuss next steps is set for Sept. 6.

"I think it's going to be more complicated coming up with injunctive relief than it was finding the liability," antitrust attorney Carl Hittinger said.

The remedies proposed by prosecutors could remake the market for online search, or have little impact at all, according to legal experts, depending on what takes place over the coming months.

Google has promised to appeal. And its lawyers could ask Judge Mehta to hold off on any orders to alter its behavior while it challenges his ruling in DC’s Circuit Court of Appeals.

"We’ve passed a key milestone, but there’s still a lot of history to be written," a spokesman for Google search rival DuckDuckGo wrote in a statement following the district court's ruling.

The judge would lose the right to impose remedies if Google is found not to have broken the law, on appeal.

And even if Google fails and is ordered to change its behavior, Judge Mehta could later adjust his orders, to better ensure competition is restored to the two markets.

A breakup

Certainly a breakup of Google’s empire has the most potential to re-order the tech universe. That could include divestitures of its Android operating system, Chrome browser, or AdWords platform — all of which steer users into Google search.

Any one of the three solutions would rip away a multi-billion dollar revenue stream from the tech giant, plus cut off data that fuels its broader search and advertising ecosystem.

Legal experts disagree about whether this will actually happen. Hittinger said it’s unlikely because Judge Mehta must select a remedy that best serves the public interest.

"You can't just yank the rug out from under the American public that's been using Google's service, now ingrained in our culture, without a substitute," Hittinger said. "Unless other competitors have a platform which is the same or better than Google, what's the public supposed to use in the meantime?"

He instead expects Judge Mehta to fashion a remedy similar to the one imposed against Xerox ( XRX ) in 1975 to end its dominance of the office-copier market.

The company opened up its ecosystem by no longer allowing it to configure its copiers so that ink cartridge suppliers and other third party components could not run on its machines.

But Bill Baer, former attorney general for the Justice Department's antitrust division, said he could foresee Judge Mehta requiring Google to divest Android or Chrome.

"The judge, in order to make this remedy meaningful, is going to have to do something that allows competition to flourish," Baer said.

"Because they're a monopolist, they charge the advertisers, who in turn charge us, a whole lot more than if the market were competitive."

Sharing data with rivals

The judge could also force Google to share more search data with rivals and force it to offer choice screens to device owners and browser users so that they can pick their preferred search engine.

A spokesman for Google search rival, DuckDuckGo, told Yahoo Finance before the trial that the company hoped remedies would require Google to share click & query data.

The data, which helps search engines track what users are searching and how they navigate to a particular website, could help DuckDuckGo and other more privacy-oriented search engines compete against Google.

Unlike Google, DuckDuckGo does not assemble user search profiles or search histories and then use that data to target users with advertisements.

Tim McGinn , an antitrust litigation attorney with Gunster, predicted that remedies would require mobile devices, browsers, and wireless carriers to let consumers choose between Google, Bing ( MSFT ) Yahoo!, DuckDuckGo, or other platforms.

"It’s possible we’ll eventually see more phones and browsers pre-programmed to use another search engine," McGinn said.

A likely scenario, the antitrust lawyers said, is for the judge to put an end to agreements that secure Google’s search engine as a default on mobile devices and internet browsers. Google pays as much as $26 billion per year to maintain its position on mobile devices like Apple and Samsung smartphones.

These agreements were at the center of Judge Mehta’s ruling, said Proskauer antitrust lawyer Colin Kass, leading him to suspect any remedies will focus on the contracts that formalize them.

"This was a relatively narrow complaint, and an even narrower ruling,” Kass said.

No 'dramatic effect'

An end to the revenue-sharing contracts would have considerable consequences for Apple ( AAPL ).

The contracts — which require Apple to install Google Search as the default across its Safari browser Spotlight Search and Siri — bring in an estimated $20 billion for Apple, each year.

Targeted search platforms like Yelp ( YELP ) and Amazon ( AMZN ) could also benefit from fewer search users being automatically directed to Google.

On the other hand, McGinn said, device manufacturers and browser services could choose Google as a default even if a court blocks Google from default placement agreements.

Plus, he said, it's possible that the court could still allow Google to secure default placements for search, but under new, non-exclusive contracts that don’t raise antitrust concerns.

Even if Google were forced to divest search-related entities, or unravel contracts for default placement, these moves may not have a dramatic effect on the company, according to Jeffries senior analyst Brent Thill.

Its bigger threats, Thill said, are from new AI-assisted search engines and recent gains made by rival Meta in attracting advertisers.

"I don't think spinning off a browser or an Android operating system is going to have a dramatic impact on the company," Thill said.

Alexis Keenan is a legal reporter for Yahoo Finance. Follow Alexis on X @alexiskweed .