PIMCO 25+ Year Zero Coupon U.S. Treasury Index ETF, formerly PIMCO 25+ Year Zero Coupon U.S. Treasury Index Fund ETF, is an exchange-traded fund. The Fund seeks to provide total return that closely corresponds to the total return of The BofA Merrill Lynch Long US Treasury Principal STRIPS Index (the Index) by investing at least 80% of its total assets (exclusive of collateral held from securities lending) in the component securities of the Index. The Index is an unmanaged index consisting of long-maturity separate trading of registered interest and principal of securities representing the final principal payment of the United States Treasury bonds with at least $1 billion in outstanding face value and a remaining term to final maturity greater than or equal to 25 years. It invests in a representative sample of securities included in the Index that collectively has an investment profile similar to the Index. The Fund’s investment advisor is Pacific Investment Management Company LLC.