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CVS Health Corp. (CVS - Get Report)  said on Wednesday that its prescription benefit management subsidiary, CVS Caremark, will roll out a new pricing model that it said will offer greater "drug cost predictability and pricing simplicity."

According to the company, the new model will allow CVS to pass through 100% of drug rebates to its health plan clients. CVS, which completed its $69 billion acquisition of health insurer Aetna Inc. last week, said it would begin rolling out the new model starting in 2019.

So-called PBMs and the rebates they receive from drug companies have more recently come under scrutiny as well as criticism from both policymakers and the pubic, who have been calling for greater transparency related to their financial arrangements.

CVS shares ended the day Tuesday down 61 cents at $78.91 on the New York Stock Exchange. U.S. markets were closed Wednesday to commemorate the death of former U.S. President George H.W. Bush.