In 2007, meanwhile, CVS, the big retail drugstore chain, went "upstream," buying Caremark, another PBM, in the process generating lots of complaints from independent pharmacies that the Caremark PBM is steering much of its retail business to CVS. The independents now fear any further consolidation of PBMs will only add to their woes as more and more prescriptions are routed through the PBMs' own mail-order pharmacies rather than through the corner drugstore.