Pacific Investment Management Co. was replaced by TCW Group Inc. as the manager of a $1.3 billion bond fund offered by Columbia Management Investment Advisers LLC.

The fund, previously known as the Pimco Mortgage-Backed Securities Fund, will become the TCW Core Plus Bond Fund, according to a statement today from Los Angeles-based TCW.

Carlos Melville, a spokesman for Columbia Management, and Mark Porterfield, a spokesman for Pimco, didn’t immediately respond to e-mails seeking comment on the change.