Medco Health Solutions (MHS) said it would buy back as much as $500 million worth of its own shares.

Monday's announcement by the Franklin Lakes, N.J., pharmacy benefit manager comes just days after Medco completed its $2.3 billion acquisition of Accredo Health.

"This stock repurchase plan reflects the desire of Medco's Board to drive continued value for our shareholders," said CEO David Snow. "The Board will regularly review the repurchase program, along with other strategies, such as our recently completed acquisition of Accredo Health, as part of an ongoing effort to optimize the use of our strong cash flow to enhance Medco's growth and shareholder value."

Medco shares fell 56 cents Monday to $49.10.