Larry W. Keele, manager of the $1.9 billion Vanguard Convertible Securities Fund, will retire at the end of June, Vanguard announced Tuesday.

Keele is a principal and co-founder of Oaktree Capital Management L.P., which has provided investment advisory services to the fund since 1996. He will remain a member of Oaktree’s board of directors, Vanguard says.

As part of the transition, Stu Spangler will join the management team of the fund and will co-manage the U.S. portion of the portfolio along with Keele until his retirement. Spangler will then manage the fund.

Spangler joined Oaktree’s convertible securities team as an analyst in 1997 after serving as a convertible securities portfolio manager for Aon Corp., a provider of insurance and consulting services.