There are many multinational supermarket stores open at 5 am in  the USA but here is the list of the best supermarkets stores names, no. of stores, and timing:

1. Wal-Mart: 4253 stores, 9 AM to 9 PM.
2. Albertson's cos.Inc: 2323 stores, 9 AM to 9 PM.
3. Whole food market: 500 stores, 9 AM to 9 PM.
4. Meijer Inc: 240 stores, 9 AM to 9 PM.
5. Aldi Inc: 2500 stores, 9 AM to 9 PM.
6. Kroger Co: 2759 stores, 9 AM to 9 PM.
7. Publix Supermarket: 1236 stores, 9 AM to 9 PM.