CVS

CVS & its CVS Caremark unit are the top providers of prescriptions in the United States, filling more that 1 billion per year. It is the nation's largest pharmacy retailer with approximately 6,200 stores in 38 states. The company has been in operations for more than 40 years and started in Lowell, Massachusetts.

1. 1967: Operates first stores with pharmacies
2. 1972: Acquires Clinton Drug and Discount Stores
3. 1977: Acquires Mack Drug stores
4. 1990: Acquires Peoples Drug stores
5. 1997: Acquires Revco stores
6. 1999: Launches CVS.com
7. 2006: Merges with Caremark to create CVS Caremark Corporation