Who knows. He's a large donor, but donors have trouble suing institutions over conditional gifts. So even if he made a gift that was conditional on beating the S&P, which would be a rather extraordinary string to attach to a gift, odds are stacked against him.
Guess: he knows he doesn't have a winning case but wants to raise hell. If the fund moves to more passive management then he won either way.
His personal basis for standing is unclear even from the more detailed article, but part of it is claims for class action standing by a group of recent students on behalf of all students of the last decade years.
He's given them money, and wants it used prudently:
> He has donated about $5 million to his alma mater and received various honors and officials designations from the university, including the chairmanship of its investment committee in the 1990s.
