Marketplace business models are easily recognizable, but they aren’t easily constructed. To unlock the benefits of a marketplace, enterprises must first embrace their unique vertical expertise. Tech leaders must partner with digital business strategy leaders to compose platforms that digitalize the firm’s unique value proposition. This report illustrates how one group purchasing organization (GPO) went beyond traditional marketplace principles to build a first-of-its-kind platform that allows US government buyers to make purchases from hundreds of leading suppliers using compliant, cooperative contracts with a modern e-commerce experience. The result is streamlined procurement for municipal governments.