5. CDW

2016 Rank: 5

Top Executive: Thomas Richards, Chairman & CEO

Location: Vernon Hills, Ill.

www.cdw.com

CDW services help manage customers' cloud, data center, security, collaboration, and mobility requirements. The company's services include pre-shipment configuration of hardware and software, professional services, managed services including colocation and cloud, extended warranty and maintenance services, and leasing and international services. Its most recent services expansion was late last year's introduction of cloud planning services.