The so-called statement of objections, which could be announced tomorrow will mark another escalation in a long-running saga that's already led to a trio of EU penalties totaling more than $8.6 billion.

The new charges will target the core of the Alphabet unit's ad tech business model, according to people familiar with the matter who spoke on condition of anonymity. Google's advertising business is by far its most successful, accounting for about 80 per cent of its annual revenue. In 2022, its ad sales amounted to about $225 billion.

The new complaint is the most significant in the current five-year mandate of the European Commission, the EU's antitrust watchdog, one of the people said.