A showdown between the US government and the four big tech giants - Amazon, Apple, Facebook and Google - is set to be postponed.
The hearing was due to question the companies' dominance in their fields of e-retail, smartphone software, social media and search.
It is expected to be delayed to allow the politicians to attend a service for the deceased civil rights activist and congressman John Lewis.
A new date has yet to be confirmed.
Facebook's Mark Zuckerberg, Google's Sundar Pichai, Amazon's Jeff Bezos and Apple's Tim Cook were due to appear via video link before the antitrust panel of the House of Representatives Judiciary committee.
The meeting would have been be the culmination of a year's investigation into the companies.
The panel is set to release a report afterwards recommending whether legislation is needed to end the companies' dominance of their respective sectors.