Drugstore chain CVS Health cut its 2016 adjusted earnings forecast, citing slowing prescription growth and pharmacy network changes that will cause retail prescriptions to begin migrating out of its pharmacies this quarter.
Shares of the No. 2 U.S. drugstore chain by store count were down about 13 percent at $72.50 in premarket trading on Tuesday.
Rival Walgreens Boots Alliance's shares were down 6 percent.
CVS cut its 2016 adjusted earnings forecast to $5.77-$5.83 per share from its prior forecast of $5.81-$5.89 per share.
Analysts on average had expected earnings of $5.85 per share, according to Thomson Reuters I/B/E/S.
Net income attributable to CVS rose to $1.54 billion, or $1.43 per share, in the third quarter ended Sept. 30, from $1.25 billion, or $1.11 per share, a year earlier.
Excluding items, CVS earned $1.64 per share.
Net sales rose 15.5 percent to $44.62 billion, helped by strong demand for its pharmacy benefit management services, but missed the average analysts' estimate of $45.29 billion.
(Reporting by Gayathree Ganesan in Bengaluru; Editing by Martina D'Couto)