The chief executives of four of the world's largest tech companies, Amazon.com Inc, Facebook Inc, Apple and Alphabet's Google, testified before the panel in July.

During the hearing, the four CEOs parried a range of accusations that they crippled smaller rivals in their quest for market share. The four companies have a combined market value of about $5 trillion.

The House antitrust subcommittee plans to hold a hearing on Friday on proposals to strengthen antitrust laws and restore online competition as it nears the release of this long-awaited report on Big Tech.

The date of release of the report can still be moved, the source said.

The U.S. Justice Department is also probing the big four tech platforms. Facebook and Amazon are also facing inquiries by the Federal Trade Commission, while U.S. states attorneys general are looking at Facebook and Google.

By Nandita Bose