A. Security Valuation: Securities are valued as of the close of trading on the New York Stock Exchange (generally 4 p.m., Eastern time) on the valuation date. Bonds and temporary cash investments are valued using the latest bid prices or using valuations based on a matrix system (which considers such factors as security prices, yields, maturities, and ratings), both as furnished by independent pricing services. Structured debt securities, including mortgages and asset-backed securities, are valued using the latest bid prices or using valuations based on a matrix system that considers such factors as issuer, tranche, nominal or option-adjusted spreads, weighted average coupon, weighted average maturity, credit enhancements, and collateral, as furnished by independent pricing services. Investments in Vanguard Market Liquidity Fund are valued at that fund's net asset value. Securities for which market quotations are not readily available, or whose values have been affected by events occurring before the fund's pricing time but after the close of the securities’ primary markets, are valued at their fair values calculated according to procedures adopted by the board of trustees. These procedures include obtaining quotations from an independent pricing service, monitoring news to identify significant market- or security-specific events, and evaluating changes in the values of foreign market proxies (for example, ADRs, futures contracts, or exchange-traded funds), between the time the foreign markets close and the fund’s pricing time. When fair-value pricing is employed, the prices of securities used by a fund to calculate its net asset value may differ from quoted or published prices for the same securities.
B. Foreign Currency: Securities and other assets and liabilities denominated in foreign currencies are translated into U.S. dollars using exchange rates obtained from an independent third party as of the fund’s pricing time on the valuation date. Realized gains (losses) and unrealized appreciation (depreciation) on investment securities include the effects of changes in exchange rates since the securities were purchased, combined with the effects of changes in security prices. Fluctuations in the value of other assets and liabilities resulting from changes in exchange rates are recorded as unrealized foreign currency gains (losses) until the assets or liabilities are settled in cash, at which time they are recorded as realized foreign currency gains (losses).
C. Futures Contracts: The fund uses futures contracts to invest in fixed income asset classes with greater efficiency and lower cost than is possible through direct investment, to add value when these instruments are attractively priced, or to adjust sensitivity to changes in interest rates. The primary risks associated with the use of futures contracts are imperfect correlation between changes in market values of bonds held by the fund and the prices of futures contracts, and the possibility of an illiquid market. Counterparty risk involving futures is mitigated because a regulated clearinghouse is the counterparty instead of the clearing broker. To further mitigate counterparty risk, the fund trades futures contracts on an exchange, monitors the financial strength of its clearing brokers and clearinghouse, and has entered into clearing agreements with its clearing brokers. The clearinghouse imposes initial margin requirements to secure the fund’s performance and requires daily settlement of variation margin representing changes in the market value of each contract. Any securities pledged as initial margin for open contracts are noted in the Schedule of Investments.
Futures contracts are valued at their quoted daily settlement prices. Fluctuations in the value of the contracts are recorded as an asset (liability).
D. Forward Currency Contracts: The fund enters into forward currency contracts to protect the value of securities and related receivables and payables against changes in future foreign exchange rates. The fund’s risks in using these contracts include movement in the values of the foreign currencies relative to the U.S. dollar and the ability of the counterparties to fulfill their obligations under the contracts. The fund mitigates its counterparty risk by entering into forward currency contracts only with a diverse group of prequalified counterparties, monitoring their financial strength, entering into master netting arrangements with its counterparties, and requiring its counterparties to transfer collateral as security for their performance. In the absence of a default, the collateral pledged or received by the fund cannot be repledged, resold, or rehypothecated. The master netting arrangements provide that, in the event of a counterparty’s default (including bankruptcy), the fund may terminate the forward currency contracts, determine
