The plan had placed Western Asset Management on watch earlier this year.
The agency expects to commence a contract on July 1.
The retirement fund currently works with fixed-income consultant RVK.
The county rehired the investment consultant that serves on behalf of its defined benefit plan, OPEB trust and LOSAP program trust.
The plan is also conducting a consultant search for informational purposes.
The manager hire concludes a domestic all-cap equity index manager search, which the program launched in March.
The plan is looking to commit $10 million to the asset class for pacing purposes.
The pension plan committed up to $80 million to a new manager relationship.
The plan is seeking firms to handle an approximately $95 million mandate.
The firm, which seeks to lead investments in early-stage software companies at seed and series A stages, has raised more than $350 million for its inaugural fund, including a commitment from at least one large endowment.