Statement of additional information
The Statement of additional information (SAI) is a supplementary document to a mutual fund prospectus, which provides detailed ancillary information regarding the operation of the fund. It is often called "Part B" of the fund prospectus. 
|Statement of Additional Information (SAI)
The SAI conveys information about the fund that some investors find useful. The SAI affords the fund an opportunity to expand discussions of the matters described in the prospectus. The SAI generally includes the fund’s financial statements and information (or additional information) about: the history of the fund; some fund policies (such as on borrowing and concentration policies); officers, directors and persons who control the fund; investment advisory and other services; brokerage commissions; tax matters; and performance measures, such as, average annual total return."
Among the sections included in the SAI, one will usually find the following major sections: 
Vanguard SAI Table of Contents
|-- Vanguard European Stock Index (VEURX) SAI|
This section of the SAI details the fund's policy regarding such issues as borrowing, use of commodities, and limits regarding portfolio concentration in individual securities or industry sectors.
This section goes into great detail regarding the risks associated with the investments allowed by the fund's prospectus. These can include (but are by no means limited to) convertible securities, derivatives, swaps, options, currency forwards, repurchase and reverse repurchase agreements, and exchange traded funds.
Management of the fund
This section provides a close examination of a fund's distribution costs and marketing strategies. This section also provides disclosure of trustee compensation as well as trustee ownership in the fund.
Investment advisory services
This section provides details regarding the advisory contract, and provides a listing of other accounts managed by the fund manager. The fund manager's investment in the fund is also revealed.
This section reveals the amount of brokerage commissions the fund has incurred buying and selling fund securities.
Proxy voting guidelines
This section details guidelines on how the fund, as a shareholder in the companies it owns, will vote on proxy issues.