'Valeant has become toxic': An inside look at Bill Ackman's tumultuous relationship with Valeant

The US Senate has released 818 pages of Valeant-related information connected to the investigation into the pharmaceutical company's business practices.

Along with a variety of emails and documents, the dump includes a number of messages between Valeant leadership, including former CEO Mike Pearson, and Bill Ackman, hedge fund billionaire and CEO of Pershing Square.

Ackman is a huge investor in the troubled pharmaceutical company and, based on the emails, in constant communication with management. Ackman joined the board on March 21.

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