Alameda-Contra Costa Transit District Employees' Retirement Plan (AC Transit Employees' Retirement Plan) is a public pension fund based in Oakland, California. The pension fund is dedicated to providing a secure and predictable source of retirement income for eligible employees, retirees, and beneficiaries. Alameda-Contra Costa Transit District is a public bus system in California, serving 13 cities and adjacent unincorporated areas in Alameda and Contra Costa counties. The assets of the pension fund are managed by the Retirement Board.