WASHINGTON — They command corporations with gold-plated brands, millions or even billions of customers, and a combined value greater than the entire German economy. One of them is the world's richest individual; another is the fourth-ranked billionaire. Their industry has transformed society, linked people around the globe, mined and commercialized users' personal data, and infuriated critics on both the left and right over speech.

Now Amazon CEO Jeff Bezos, Facebook's Mark Zuckerberg, Google's Sundar Pichai and Tim Cook of Apple will answer for their companies' practices before Congress for the first time as a group. Summoned for a House hearing, they'll raise a hand (remotely) and swear to tell the truth, in the manner of tycoons of Wall Street or the tobacco industry in earlier high-octane televised shamings. It will be Bezos' first-ever appearance before Congress.

The House Judiciary subcommittee on antitrust is capping its yearlong investigation of Big Tech's market dominance with Wednesday's teleconferenced hearing spotlighting the four CEOs.

"It's mostly theater. There are few genuine facts left to gather," says Daniel Crane, a law professor at the University of Michigan who focuses on antitrust.

Still, the CEOs' approaches to the questioning are important, Crane notes. "Are they willing to admit that there's a problem with Big Tech's market power, or is it denial mode? Will they recommend innovative private solutions, or retreat into defending themselves as champions of consumer interests who play it fair?"

The bipartisan probe stands out in a capital steeped in partisanship, where Republicans and Democrats are now arguing over the size of new federal pandemic relief. It's the first such congressional review of an industry that for over a decade has enjoyed haloed status and a light touch from federal regulators.

Critics question whether the companies stifle competition and innovation and pose a danger to society. The Judiciary panel collected testimony from mid-level executives of the four firms, competitors and legal experts, and pored over more than a million internal documents from the companies.

A key question: Whether existing competition policies and century-old antitrust laws are adequate for overseeing the tech giants, or if new legislation and more funding for enforcement are needed.

Subcommittee chairman Rep. David Cicilline, a Rhode Island Democrat, has called the four companies monopolies, although he says breaking them up should be a last resort. With other Democrats, Cicilline has floated the idea of an antitrust moratorium that would block big corporations from acquiring smaller companies during the coronavirus pandemic. Republicans call the idea misguided and socialistic.

The tech companies now face legal and political offensives on multiplying fronts, from Congress, the Trump administration, federal and state regulators and European watchdogs. The Justice Department and the Federal Trade Commission have been investigating the four companies' practices, including the earlier acquisitions of smaller firms.

Facebook's fiercest critics in Congress, including liberal Democrat Sen. Elizabeth Warren and conservative Republican Sen. Josh Hawley, have put breaking up Big Tech companies on the table. And presumed Democratic presidential nominee Joe Biden has said breakups of the giants should be considered.

Short of breakup, the scrutiny of the companies across the U.S. and abroad points toward possible new restrictions on their power.

The CEOs could follow the conventional playbook for congressional "star chamber" hearings, making their case while showing some humility.

Beyond that, each company has a distinct profile, and each tech titan has his own approach and story to tell.

Bezos, the world's richest individual presiding over an e-commerce empire and ventures in cloud computing, personal "smart" tech and beyond, initially declined to testify unless he could appear with the other CEOs. He'll likely face questioning over a Wall Street Journal report that found Amazon employees used confidential data collected from sellers on its online marketplace to develop competing products. At a previous hearing, an Amazon executive denied such accusations.

Lawmakers from both parties suggested Amazon's earlier statements could be misleading and might even constitute perjury. Bezos has said, "We don't use individual seller data to directly compete with them." Amazon says it doesn't believe the Journal allegations are accurate, but has started an internal investigation.

Zuckerberg is a Capitol Hill pro by this point. He endured over five hours of grilling last fall by another House committee on hate speech, privacy, misinformation and Facebook's widely-criticized plan for a new digital currency. He also met privately with key lawmakers and with President Donald Trump, who has repeatedly criticized the tech companies and asserted without evidence that they are biased against him.

In the wake of George Floyd's death and protests against racial injustice, Facebook's handling of hate speech has recently drawn more fire than issues of competition and privacy, especially after Facebook's refusal to take action on inflammatory Trump posts that spread misinformation about voting by mail and, critics said, encouraged violence against protesters. Zuckerberg has said the company aims to allow as much free expression as possible unless it causes imminent risk of specific harms or damage.

Pichai faced his own congressional interrogation in 2018 over online privacy and data protection, the danger of digital monopolies, alleged bias against conservative viewpoints and censorship by China. He acknowledged some points but avoided the yes or no answers that lawmakers demanded. EU regulators already have concluded that Google manipulated its search engine to gain an unfair advantage over other online shopping sites in the e-commerce market, and fined Google, whose parent is Alphabet Inc., a record $2.7 billion. Google has disputed the findings and is appealing.

Attorneys general from both parties in 50 states and territories, led by Texas, launched an antitrust investigation of Google in September, focused on its online advertising business.

Apple, whose iPhone is the third-largest seller in the world, faces EU investigations over the fees charged by its App Store and technical limitations that allegedly shut out competitors to Apple Pay. Cook is expected to lay out the case that the fees Apple charges apps to sell services and other goods are reasonable, especially compared with what other tech companies collect.