Landis Zimmerman was named CIO at the $11.3 billion Howard Hughes Medical Institute, Chevy Chase, Md. Mr. Zimmerman, who will start his new job at the foundation early next year, succeeds Nestor Villarosa Santiago, who died in June. Mr. Zimmerman was CIO at the University of Pennsylvania endowment, Philadelphia, which has $3.8 billion in assets, according to the Money Market Directory. He has not yet been replaced. Mr. Zimmerman could not be reached for comment. "We're very excited to have Landis. He brings an extraordinary mix of skills," said Avice Meehan, Hughes spokeswoman.