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The shadowy system behind the high price of your drugs

Healthcare stocks are taking a hit this week. Proposed legislation that would tighten control over pharmacy benefit managers-- or PBMs-- are weighing down shares. Who are PBMs and what impact do they have on what we pay for our prescription drugs? Robin Feldman, author of Drugs, Money and Secret Handshakes, the Unstoppable Growth of Prescription Drug Prices, talks with Yahoo Finance's Julie Hyman and Adam Shapiro.