Rex Holsapple, CIO at the $8.4 billion Maine State Retirement System, Augusta, has left over a disagreement with Executive Director Gail Wright, according to a source familiar with the plan, who didn't want to be identified. Mr. Holsapple was hired by Kay Evans, Ms. Wright's predecessor, in 2002, and the two "worked well together," according to the source. When she retired and Ms. Wright replaced her, Mr. Holsapple and Ms. Wright disagreed on investment strategy, the source said. Mr. Holsapple, reached at home, declined to comment on why he left and said he has no career plans yet. His last day was June 14. Calls to Ms. Wright were not returned by press time.