Ackman responds to Buffett: You don't indict Valeant on the actions of a few people

Hedge fund manager Bill Ackman spoke with CNBC's "Fast Money: Halftime Report" on Monday as key holding Valeant Pharmaceuticals continued to tumble.. Its shares have plunged about 70 percent this year, hitting Ackman, who owned about 9 percent of outstanding shares as of March 24. During a Senate hearing last week on Valeant's drug pricing, Ackman said his first...