3M Company
Accenture [Accounting/scandalized]
ACT
Aetna
Aflac (INSURANCE, RIGHT?)
Altria Client Services, Inc.
Amazon.com
American Electric Power
American Specialty Health
Amerigroup
Amgen
Amplify
AON Corporation
Apple
Applied Materials
ARAMARK Corporation
Astellas Pharma – Rx
AstraZeneca Pharmaceuticals – Rx
AT&T
Atria Senior Living
BAE Systems
Bank of America
Barrick Gold of North America, Inc.
Battelle
Baxter – Rx
Best Buy Co., Inc.
Best Doctors
Biogen Idec
Blue Cross Blue Shield
BP America [BP=British Petroleum]
Bridgepoint Education
CenturyLink
Catamaran
Cerner Corporation
Chrysler
Cisco Systems
Citi
The Coca-Cola Company
The College Board
Comcast Corporation
CCA
CVS Caremark
Daiichi Sankyo
Daimler
Darden Restaurants
Deloitte [[!!!]]
DeVry, Inc.
The Dow Chemical Company
DTE Energy
Duke Energy
Education Management Corporation
Educational Testing Service
EMD Serono
Endo Health Solutions
ESRI
ExxonMobil Corporation  [=Rockefeller]
FMC Corporation
Ford Motor Company
Genentech [biotech]
General Electric Company
General Motors
Gilead Sciences, Inc.
GlaxoSmithKline  [Rx]
Golden Living
Grant Thornton
GTECH
Hallmark Cards, Inc.
Harley-Davidson Motor Company
HDR, Inc.
Hewlett-Packard Company
Hospital Corporation of America
Houghton Mifflin Harcourt Publishing Company
Humana
IBM Corporation
Intel
Intuit
Johnson & Johnson
JPMorgan Chase & Co.  [BANKING]
Kaiser Permanente
Knowledge Universe
Level 3 Communications, LLC
Louis Berger Group
MAXIMUS  [WELL KNOWN IN THIS FIELD!]
McKinsey & Company
Merck & Co., Inc. [Rx; see the Merck Manual]
Microsoft Corporation
Molina Healthcare, Inc.
Morgan Stanley [!!!]]
Motorola Solutions
Mylan Inc.
Nestle Waters North America
NIC, Inc.
Nike
Norfolk Southern
Northrop Grumman (defense, right?)
Novartis Pharmaceuticals USA – Rx
Novo Nordisk Inc.
Oracle USA Inc.
Pearson Education
Premier
Purdue Pharma – Rx
Pfizer
The Procter & Gamble Company – Rx
Prudential Financial
RAI Services Company
Renaissance Learning
ResCare
Sanofi – Rx look it up! Global Healthcare
SAS Institute Inc.
SCAN Health Plan
Scholastic
Shire Regenerative Medicine
Sodexo USA
South Alabama Gas District
Southern Company
State Farm Insurance
Target
TEVA Pharmaceuticals USA – Rx
TIAA-CREF
Time Warner Cable
Toyota Motor North America
TransCanada
Truven Health Analytics
Unilever United States
UnitedHealth Group
Union Pacific Railroad
Verizon Communications
VMware
Walgreen Co.
Wal-Mart Stores Inc.
Weight Watchers InternationalWellCare Health Plans, Inc.
WellPoint, Inc.
Western Governors University

Are any of these corporations nonprofits?

Sampling of the perhaps less famous ones from the list: