Investing.com -- Alphabet (NASDAQ: GOOGL ) shares fell 2.9% Friday following a Virginia court’s ruling that the tech giant had engaged in illegal monopoly practices within the online advertising technology sector. The decision, which found Google to have "wilfully acquired and maintained monopoly power" in the sale of ads on independent websites, signaled an increased likelihood of significant operational changes for the company in the near future.

The court’s ruling adds to the pressure on Google, coming after an August decision that already established its search business as an illegal monopoly. With these legal challenges, Google could be compelled to divas parts of its ad tech business, which is pivotal in how advertisers purchase ads on independent sites and how publishers sell ad space.

The government’s case against Google argued that the company exploited its market dominance to inflate prices and suppress competitors. This latest development could lead to enforced restructuring to address these antitrust concerns.

On the other side, The Trade Desk (NASDAQ: TTD ), a platform that provides technology to manage digital advertising campaigns, saw its shares rise by 5%. The company could benefit from a less concentrated ad tech market if Alphabet’s Google is required to alter its business structure. Magnite also gained.

Following the announcement, Google’s VP of Regulatory Affairs, Lee-Anne Mulholland, offered a statement, saying, "We won half of this case and we will appeal the other half. The Court found that our advertiser tools and our acquisitions, such as DoubleClick, don’t harm competition. We disagree with the Court’s decision regarding our publisher tools. Publishers have many options and they choose Google because our ad tech tools are simple, affordable and effective.”

While Alphabet faces potential upheaval, the ruling may open opportunities for other players in the online advertising industry. The market’s reaction reflects the shifting landscape, with Alphabet’s dominance under legal scrutiny and competitors like The Trade Desk poised to capitalize on any enforced changes.