[Cyph0n]

Electrical engineering. It happens, especially if you worked in R&D and continued to publish over the years. One of the professors currently teaching me spent 5 years at a startup and came back to his alma mater as an assistant professor. He's an expert on botnets and quite active, so that might be an exception haha!

[noobermin]

Returning to alma mater and being an expert in a niche is an extreme exception, on the orders of magnitude down level.

[Cyph0n]

I am aware of that. I guess it was just a bad example. I'm sure you can find other less exceptional instances though.

[tnecniv]

During my undergrad I definitely had a handful of professors that came from stints at corporate research labs.