For my projects I prefer a permissive licence, specifically the MIT No Attribution Licence. People argue that corporations will just take your code and make it proprietary. They might, but an internal fork like that means that it's difficult to benefit from improvements in the original project. So in my experience corporations don't create an internal fork, they use the code as it is. Then if they find a bug for example they will contribute the fix to the project rather than forking, because it's the easiest option.
So in other words, corporations are more likely to use code that's licensed under a permissive licence, and so they're more likely to contribute, simply out of their own self interest.
Comments
For my projects I prefer a permissive licence, specifically the MIT No Attribution Licence. People argue that corporations will just take your code and make it proprietary. They might, but an internal fork like that means that it's difficult to benefit from improvements in the original project. So in my experience corporations don't create an internal fork, they use the code as it is. Then if they find a bug for example they will contribute the fix to the project rather than forking, because it's the easiest option.
So in other words, corporations are more likely to use code that's licensed under a permissive licence, and so they're more likely to contribute, simply out of their own self interest.