Which companies have the toughest interviews?

According to Glassdoor, the following companies have the toughest interviews:

1. McKinsey & Co.

2. Jane Street Capital

3. Cree

4. Bain & Co.

5. Boston Consulting

6. Palantir Technologies

7. Teach for America

8. A.T. Kearney

9. Red Ventures

10. BP

11. ZS Associates

12. Procter & Gamble

13. Salesforce.com

14. Altria

15. Oliver Wyman

16. Bridgewater Associates

17. Stryker

18. Amazon.com

19. eBay

20. Gallup