Four of tech’s most prominent chief executives — Sundar Pichai of Google parent Alphabet Inc. GOOGL, -0.50% GOOG, -0.47% , Jeff Bezos of Amazon.com Inc. AMZN, -0.57% , Tim Cook of Apple Inc. AAPL, -0.53% and Mark Zuckerberg of Facebook Inc. FB, -0.26% — are scheduled to answer questions from lawmakers about their business practices and enormous influence over the economy and Americans’ day-to-day life. (The hearing, originally scheduled for Monday, was delayed until Wednesday due to plans for the late Rep. John Lewis to lie in state at the U.S. Capitol.)

Appearing via video links, the quartet — whose companies are collectively worth $5 trillion — should expect withering queries and statements from the House Judiciary Antitrust Subcommittee as investigations into their business practices by the Justice Department and Federal Trade Commission deepen. Senior subcommittee aides held a call with members of the media on Thursday and outlined their planned approach.

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Bezos and his corporate brethren are under the regulatory microscope for the considerable sway they hold over multiple markets, ranging from shopping (via Amazon and Google), entertainment (Apple and Google’s YouTube), news and how-to tutorials (Google search), and socializing (Facebook). The steep ascent of Big Tech, which is fueling a resurgent stock market despite a deepening pandemic, underscores the enduring power of the industry as consumption escalates in a work-from-home economy.

“It won’t be a condemnation as much as part of an ongoing investigation,” Matt Stoller, research director at the American Economic Liberties Project and author of “Goliath: Hundred Year War between Monopoly Power and Democracy,” told MarketWatch in a phone interview. “The committee members are trying to understand their business models, where their revenue comes from, and how they operate.”