https://github.com/twitter/ "100 public repos"

https://github.com/facebook "95 public repos"

https://github.com/37signals "44 public repos"

https://github.com/linkedin "49 public repos"

https://github.com/soundcloud "131 public repos"

These aren't "Open-Source companies". They contribute greatly to open source projects. But aren't themselves "Open-Source".