A trial over the long-running case had just begun on Wednesday, with defendants accused of overpaying the US government in 2019 when they engineered a $5 billion settlement for alleged privacy violations in the scandal.

Sources familiar with the matter confirmed the settlement to AFP, without providing details.

The settlement comes the same day that Marc Andreessen, one of Silicon Valley's most influential venture capitalists and a board member of the company now known as Meta, was to take the stand.

Zuckerberg himself was expected in the Wilmington, Delaware courtroom on Monday.

Silicon Valley investor Peter Thiel and former Meta top executive Sheryl Sandberg were also expected to face questioning in the court.

Cambridge Analytica was a political consulting firm that was found to have improperly harvested personal data from millions of Facebook users for targeted political advertising, particularly during the 2016 US election and Brexit referendum.

The scandal thrust Facebook and Zuckerberg in particular into a political firestorm, leading to major regulatory changes and public scrutiny of tech companies' data practices.

The shareholders in the lawsuit alleged that the board members conspired to pay more to the US government in exchange for ensuring that Zuckerberg would not be named personally for wrongdoing in the settlement.

Longtime observers of the company were hoping that the trial would expose inside details of how Zuckerberg and the Facebook executives handled the scandal.

Zuckerberg was under huge pressure at the time from US and European lawmakers amid widespread allegations that Russia and other bad actors were weaponizing Facebook to sow chaos around major elections in the West.

The multi-faceted case also alleged insider trading at the time of the events, with board members to be questioned about the timing of their share sales before the scandal was made public.