Mark A. Barnard, managing director of private investments at the Howard Hughes Medical Institute, Chevy Chase, Md., is leaving in June, Mr. Barnard said in an e-mail.
While he is retiring, he said he expects to remain active in other endeavors. He will remain with the institute as a part-time adviser through the end of November.
Greg DeNinno, currently director of private investments, will succeed Mr. Barnard as managing director of private investments. Mr. DeNinno plans to add “an experienced investor to the team in the near term,” Mr. Barnard said.
The institute's endowment had $18.2 billion in assets as of Aug. 31.