Many know UnitedHealth Group (NYSE:UNH) as the largest health insurance provider in the U.S., but you may not know it as the nation's third largest pharmacy benefit manager, or PBM, after Express Scripts (NASDAQ: ESRX) -- which recently acquired Medco -- and CVS Caremark (NYSE: CVS). In recent years, Medco has managed the pharmacy benefits for UnitedHealth's commercial customers, but UnitedHealth has ended that relationship and is bringing all PBM services in-house. This cost-cutting move by UnitedHealth should save the company hundreds of millions of dollars, but represents the loss of a huge customer for Express Scripts. Is this move part of a larger trend of companies cutting costs by bringing PBM services in-house? That could have major implications for investors, as Motley Fool analyst Brenton Flynn outlines in the video below.

Brenton Flynn has no positions in the stocks mentioned above. The Motley Fool owns shares of Express Scripts. Motley Fool newsletter services recommend Express Scripts and UnitedHealth Group. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.