WASHINGTON (BLOOMBERG, AFP) - United States antitrust officials refiled their monopoly lawsuit against Facebook, seeking to salvage the landmark case that a judge threw out in June.

The Federal Trade Commission on Thursday (Aug 19) filed the new complaint in federal court in Washington, alleging that Facebook violated antitrust laws by buying Instagram and WhatsApp in order to eliminate them as competitors. The FTC is asking the court to unwind the acquisitions, as in the previous complaint.

"After failing to compete with new innovators, Facebook illegally bought or buried them when their popularity became an existential threat," Ms Holly Vedova, the acting director of the agency's competition bureau, said in a statement. "This conduct is no less anticompetitive than if Facebook had bribed emerging app competitors not to compete."

The agency is trying to revive the case after US District Judge James Boasberg in June dismissed it, saying the agency failed to provide enough detail to support its claim that Facebook has a monopoly in the social-media market. He had given the FTC 30 days to fix the error and refile, and the commission won an extension until Aug 19.

The FTC said the new complaint provides details to bolster the agency's claim that Facebook has dominant market shares in the US personal social-networking market and has the power to exclude competition. The FTC's original complaint numbered 53 pages, while the new one is 80.

"It is unfortunate that despite the court's dismissal of the complaint and conclusion that it lacked the basis for a claim, the FTC has chosen to continue this meritless lawsuit," Facebook said in a statement. "Our acquisitions of Instagram and WhatsApp were reviewed and cleared many years ago, and our platform policies were lawful."

Facebook shares slipped less than 1 per cent at 2.46pm in New York, trading at US$354.49 (S$483.58). The stock has climbed about 30 per cent this year.

The Facebook case, first filed in December, presents an early test for FTC Chair Lina Khan, who was named head of the agency in June by President Joe Biden. Ms Khan is a leading advocate for taking a more forceful antitrust stance against companies and is already taking steps to bolster the agency's authority.

Facebook sought to bar Ms Khan from participating in the case, arguing that her academic writing about the company and her work on the House antitrust panel, which investigated Facebook and other tech platforms, showed she is biased.

The FTC said in its statement that the agency's general counsel reviewed Facebook's recusal petition and dismissed it. The FTC voted 3-2 to file the amended complaint, with Ms Khan joining the agency's two other Democrats in favour of the case, which the Republican commissioners voted against.

"As the case will be prosecuted before a federal judge, the appropriate constitutional due process protections will be provided to the company," the FTC said.

The lawsuit is part of a broad effort by lawmakers and competition enforcers to rein in the power of the biggest US tech companies. Besides the Facebook case, the Justice Department and state attorneys general across the country have multiple lawsuits pending against Google, while Democrats and Republicans on Capitol Hill are pushing forward with a raft of bills that would impose new restrictions on how the companies do business.

Democratic Senator Amy Klobuchar of Minnesota, who chairs the Senate antitrust panel, cheered the new complaint.

"Facebook's long history of anticompetitive behaviour is no secret," said Ms Klobuchar in a statement. "The company's acquisitions of Instagram and WhatsApp have made the digital landscape less competitive, ultimately harming consumers."

Mr Alex Petros of the consumer group Public Knowledge, welcomed the new filing and said it should address the concerns noted by Judge Boasberg.

"While the case against Facebook has been re-invigorated today, we cannot lose sight of the immediate need for congressional and executive action to rein in Big Tech," Mr Petros said.

Mr Mandeep Singh, a Bloomberg Intelligence senior technology industry analyst, said of the matter: "This is more likely to lead to remedies like opening up its APIs (application programming interfaces) or allowing data portability for users outside its family of apps, rather than a break up. We think this is unlikely to hurt top-line growth in the near-to-medium term given Facebook's first-party advantage."

Republican FTC member Christine Wilson said in a statement it was "bad policy" to try to undo mergers that were previously approved by regulators.

Mr Ryan Young of the Competitive Enterprise Institute said that the FTC complaint "relies heavily on wordplay" to define Facebook as a monopoly.

"It argues that Facebook dominates the market for 'personal social networking services', then defines that term in just such a way that excludes TikTok, Twitter, Clubhouse, Discord and others from that market," Mr Young said. "Any market is a monopoly if you define it narrowly enough, and that is the only thing the FTC's complaint successfully proves."

Supporters of the Facebook lawsuit said Judge Boasberg's decision illustrated the legal barriers the government faces in bringing monopoly cases. Advocates for reform say court decisions over decades have effectively allowed dominant companies to engage in anticompetitive tactics and that Congress must give enforcers new authority.

Judge Boasberg not only threw out the FTC's case. He also dismissed a parallel case by state attorneys general led by New York, without giving them an opportunity to try again. The judge said the states waited too long to challenge Facebook's acquisitions. Facebook bought Instagram in 2012 and WhatsApp in 2014. The legal doctrine that applied to the states does not apply to the FTC. The states have filed an appeal seeking to reverse the judge's decision.

In the new lawsuit, the FTC argued that "personal social networking services are a unique and distinct type of online service", in an effort to counter Facebook's claim that people have numerous choices for connecting with people online.

Using this definition, the FTC said, Facebook controls more than 65 percent of the market with its core social network and Instagram, giving it monopoly power.

The new lawsuit maintained that TikTok - the popular Chinese-owned video app that Facebook claims is a rival - is "a content broadcasting and consumption service that is not an acceptable substitute for personal social networking services".

The new FTC complaint also provides details about Facebook's active users and time spent on the platform based on Comscore data. The FTC said Facebook's share of time spent by users of social network apps in the US has exceeded 80 per cent since 2012 and that its share of daily active users has exceeded 70 per cent since 2016.

Much of the new data presented by the FTC is redacted in the complaint, however.

As evidence of Facebook's power over the market, the FTC pointed to profit margins that it said have "significantly exceeded" the average for companies in the S&P 500 Index since 2013.

And despite degrading the quality of its product, including by "misusing or mishandling user data", the company has not suffered a significant loss of users, the FTC said.

As the sixth-largest public company in the world based on stock market value in US dollars, investors believe the company's monopoly power is durable, the FTC said.

In addition to targeting the Instagram and WhatsApp deals, the FTC accused Facebook of engaging in anticompetitive conduct by only allowing third-party apps to connect to its platform on condition that they do not compete against Facebook. The FTC argued that the policy was intended to extinguish competitive threats.

In his June decision, Judge Boasberg had dismissed that part of the case, saying that under existing antitrust law established by the courts, companies do not have an obligation to do business with other firms and can "refuse to deal" even to prevent a rival from competing.

"A monopolist has no duty to deal with its competitors, and a refusal to do so is generally lawful," Judge Boasberg wrote. "The FTC, therefore, cannot get anywhere by reframing Facebook's adoption of a policy of refusing to deal with all competitors as the execution of an unlawful scheme of monopoly maintenance."