The Fund seeks to achieve its investment objective by investing under normal circumstances at least 80 percent of its total assets exclusive of collateral held from securities lending in the component securities of the RAFI ESG US Index. The Fund may invest the remainder of its assets in cash, securities and instruments that are not Component Securities, but which PIMCO believes will help the Fund track its Underlying Index. The Underlying Index is a long-only, smart beta index that seeks to achieve the dual objectives of social responsibility and long-horizon outperformance of the broad market.