BlackRock co-founder Keith Anderson, who is a vice chairman and the firm’s global chief investment officer for fixed income, will leave the New York-based firm, the company announced December 13, according to a letter to clients announcing his departure. Anderson wants to run an investment fund of “his own,” but will maintain ties with BlackRock as an advisor until March, according to the company.

Stepping into Anderson’s shoes is BlackRock’s co-head for fixed income, Scott Amero, filling both the vice chairman and chief investment officer for fixed income posts. BlackRock’s Chairman, Asia, Peter Fisher, will become co-head of the fixed income portfolio management group, the client letter says, adding that the firm is beefing up the fixed-income top management team with four addditional members. They are: as co-heads of U.S. fixed income, BlackRock promoted Andy Phillips and Stu Spodek; leading non-U.S. fixed income will be co-heads Andrew Gordon and Scott Thiel.

BlackRock, with $1.3 trillion under management as of September 30, merged with Merrill Lynch Investment Managers in 2006 (MLIM), which owns a stake of about 49% of the firm; PNC Financial Services Group owns about 34% of BlackRock, according to the firm’s Web site.