Google and the US Justice Department have begun delivering closing arguments in the most significant antitrust trial in 25 years, over whether the tech giant’s search advertising practices constitute an illegal monopoly.

The Justice Department argued Google’s payments of tens of billions to companies such as wireless carriers and hardware makers enabled it to stifle competition and retain its monopoly position.

Witnesses testified that the company made $26.3 billion (£20.96bn) in such payments in 2021 and paid Apple alone $20bn in 2022 to ensure it was the default search on browsers and devices such as smartphones.

“Google winning agreements because it has a better product is not a harm to the competitive process, even if it gives it scale to improve its product,” John Schmidtlein, a lawyer from Williams & Connolly representing Google, told the court.

‘Anti-competitive conduct’

Kenneth Dintzer, a lawyer for the Justice Department, said Google’s “anti-competitive conduct harms competition and is self-perpetuating”.

“Google wouldn’t pay billions of dollars” to be the default if it were not a “powerful way to drive searches”, he added.

Google lawyer John Schmidtlein said on Friday that the company’s share of US digital advertising revenue has steadily decreased under pressure from platforms such as TikTok, Facebook, Instagram and Amazon.

He said Google is constantly working to innovate in its search advertising products, something it would not need to do if it were a monopolist, Schmidtlein argued.

The case is the most high-profile since the DOJ faced off against Microsoft over the use of Windows’ dominant market share to sideline competing web browsers.

Play Store injunction

In a separate antitrust case, Google in a filing to San Francisco federal court asked a judge not to impose changes to its Play app store proposed by Fortnite developer Epic Games.

In March Epic asked US District Judge James Donato to force Google to make it easier for users to download apps from other sources and to allow developers more flexibility in offering and charging for purchases.

The company said it should be allowed to offer its Epic Games Store on Android “without delays and barriers”.

In last week’s filing Google said Epic’s proposal “would make it nearly impossible for Google to compete”.

A hearing on the proposed injunction is scheduled for 23 May.