Not a lawyer but I've participated in "technology transfer" at a university.
At University of Washington one of the standard deals is 27% for the inventors (for patent license revenue). Of course every deal is negotiable. When you use university resources such as lab space and students the university will take some financial share.
When it comes to equity stake in a startup the deal negotiated becomes much more tricky of course and the university may maintain an equity stake in the company in exchange for exclusive licensing of the patents.
"Researchers’ patents are often held by the institutions where they work."
I wonder what the law is around that ... what percentage are the discoverers legally entitled to?
If the answer is obscene, what efforts have been made to fix that?