Clifford A. Sheets will retire as chief investment officer of the Montana Board of Investments, Helena, in October, said David Ewer, executive director.
Search efforts for a replacement will begin this week, Mr. Ewer said, but he could not provide details.
The board oversees $16.6 billion in assets, which includes $10 billion in pension fund assets.
Mr. Sheets was appointed CIO in 2005.
