Complex sentence: Computer Enterprises, Inc. (d.b.a. CEI) is a leading provider of IT staffing, serving 60% of the Fortune 50 and are one of the few mid-size companies that have been assessed at CMMi Level 5.
Split into simpler sentences: Computer Enterprises, Inc. (d.b.a. CEI) is a provider of IT staffing, serving 60% of the Fortune 50. CEI is one of the few mid-size companies that have been assessed at CMMi Level 5.