CVS Health Corp. CVS, +1.98% said Walmart Inc. WMT, -1.02% has decided to leave the CVS Caremark pharmacy benefit management (PBM) commercial and Managed Medicaid networks. "At a time when everyone is working hard to find ways to reduce health care costs, Walmart's requested rates would ultimately result in higher costs for our clients and consumers," said CVS Caremark President Derica Rice. ""While we have enjoyed a long relationship with Walmart as a low cost provider in our broad national networks, based on our commitment to helping our clients and consumers manage rising pharmacy costs, we simply could not agree to their recent demands for an increase in reimbursement." CVS Caremark has requested Walmart to continue to fill prescriptions as an in-network participating pharmacy through April 30, 2019. CVS said Walmart will continue to participate in the CVS Caremark Medicare Part D pharmacy network, and Walmart's Sam's Club remains in the CVS Caremark pharmacy networks. CVS does not expect Walmart leaving its PBM networks to have a material impact on 2019 financial results. CVS shares slipped 0.5% in premarket trade while Walmart's stock was inactive. Over the past three months, CVS's stock has shed 10.6%, Walmart shares have gained 1.2% and the Dow Jones Industrial Average DJIA, -0.87% has shed 5.3%.