“We believe that your administration must confront the threats posed by the monopolistic Big Tech companies,” said the letter, which seeks the exclusion of executives, lobbyists and consultants with ties to Alphabet Inc.’s GOOGL, +0.48% GOOG, +0.48% Google, Amazon.com Inc. AMZN, +0.14%,Apple Inc. AAPL, +1.24%, Facebook Inc. FB, -1.31% and Microsoft Corp. MSFT, +1.83%.

All but Microsoft are facing federal and state investigations for their business practices.

“We believe that eliminating the decades-old revolving door between Silicon Valley and your administration will only help your cause,” according to the letter, signed by consumer rights, antitrust reform, and labor and progressive organizations that include Public Citizen, American Economic Liberties Project and Open Markets Institute.

The five companies targeted in the letter were not immediately available for comment.

Privacy advocates and antitrust observers say they are alarmed by the number of individuals with links to Silicon Valley who are part of Team Biden.

Incoming White House chief of staff Ron Klain’s deep ties to the tech world make him the first major name from the industry to join the Biden administration.