CVS Health Corp. CVS, -1.27% announced Wednesday that CVS Caremark, its prescription benefit management (PBM) subsidiary, will be rolling out a new model of pricing it says will offer greater "drug cost predictability and pricing simplicity." Under the model, CVS plans to pass through 100% of drug rebates to its health plan clients and says it will be accountable for the impact of drug price inflation and shifts in drug mix. CVS, which completed its $69 billion acquisition of health insurer Aetna last week, said it would begin rolling out the new model starting in 2019. PBMs and the rebates they receive from drug companies have come under increasing scrutiny and criticism in the past two years, with policymakers and clients calling for greater transparency of their financial arrangements. Shares of CVS have increased 8.8% in the year to date, while the S&P 500 SPX, -2.37% has gained 1%.