Denny Hesse will step down June 1 as co-head of global fixed income at Brinson Partners, a company spokesman said today. Hes retiring for personal and family reasons, the spokesman said. Norman Cumming, former co-head with Mr. Hesse, will become the groups sole head and move to Chicago from London, reporting to CIO Gary Brinson. The moves are part of a greater restructuring of Brinsons fixed-income team following the merger of Brinson Partners parent company Swiss Bank Corp. and Union Bank of Switzerland last summer. The firm will integrate its New York and Chicago U.S. investment grade bond offices. Ranji Nagaswami, formerly of UBS, and Greg Smith are co-heads of the new team. There will be no layoffs due to the changes, Mr. Brinson said. Brinson currently has 98 investment professionals worldwide in fixed income. Meanwhile, Joe Pratt and Mike Humphries will serve as co-heads of market allocation and strategy, reporting to Mr. Cumming. Mr. Pratt also will become deputy head of fixed income, while maintaining his responsibilities as a strategist.