The European Union's second-highest court will rule Wednesday on whether antitrust authorities in Brussels went too far in handing Google a 2.4-billion-euro ($2.8-billion) fine for search engine dominance.
The decision by the Luxembourg-based General Court could undo or demand modifications to the landmark decision, taken by the European Commission in 2017.
The verdict on Wednesday centres on Google's shopping service and is one of three cases against the search engine giant currently moving through the EU's drawn-out appeals system.
At the time, the fine was the EU's biggest ever. But it was later exceeded by a 4.3-billion-euro fine against Google over Android, the company's smartphone operating system.
As it lodged its appeal, Google argued the EU was "wrong on the law, the facts, and the economics" in the search engine case.
The decision by the General Court is not necessarily the end of the story as both sides can later turn to the EU's highest court, the European Court of Justice, for a final say.
A Google victory would be a rebuke to the EU's antitrust supremo Margrethe Vestager, who burst onto the scene in Brussels by scrapping her predecessor's more conciliatory approach to the US tech titan.
Vestager lost in the same court in a major case against Apple and Ireland, in which her teams had ordered the iPhone maker to repay 13 billion euros plus interest to the Irish taxpayer. The EU has appealed the court's ruling.
The shopping fine for Google came after seven years of investigation launched by complaints from other price-comparison services that saw traffic plummet against the tech giant's own version, Google Shopping.
If the Luxembourg court upholds the decision, experts believe that Google's similar forays into vacation rentals and job ads could be next in the EU commission's firing line.
Rivals dissatisfied
Along with paying the fine, Google was told to remedy the problem identified by the EU case, even as the appeal moved forward.
The company tweaked its search display to give more prominence to rival shopping aggregators, as well as tourist and travel advice sites such as Tripadvisor and Yelp.
But many rivals are deeply dissatisfied with Google's fixes, believing they do nothing to guarantee fair competition in search results.
The General Court showdown was "a sideshow", said Richard Stables, from price-comparison site Kelkoo.
"What really matters… is stopping Google from repeating its behaviour in the future and protecting European consumers," he said.
Win or lose, the commission, the EU's antitrust enforcer, will point to new legislation expected for next year that would impose tough rules on Big Tech.
One of the laws, the Digital Markets Act, sets a clear list of Do's and Don'ts for internet "gatekeepers" that includes drastic limits on how Google, or other giants, can squeeze out rivals on their platforms.
