Big clients drop Caremark

CVS shares hammered over billions in lost revenue

Shares of CVS Caremark are off more than 20 percent this morning – erasing about $11 billion in value – after its CEO said the company's pharmacy benefit management unit has lost several big clients for 2010.

Chairman and CEO Tom Ryan, who bought Nashville-based Caremark for $27 billion in 2007, told analysts and investors on his company's conference call this morning that a number of clients are taking their PBM business elsewhere come Jan. 1.

At about 10:10 a.m., CVS shares (Ticker: CVS) were off close to 21 percent at $28.73, erasing seven months worth of gains. When CVS acquired Caremark 31 months ago, its shares were changing hands at more than $34.