SPIP aims for total TIPS market coverage. Its index includes TIPS held by the Federal Reserve, in contrast to rivals SCHP & TIP. It selects and weights constituents by market value, and narrows its pool by only choosing investment grade TIPS with at least one year remaining maturity. The fund uses a sampling method in tracking the index, which means it will invest in a sample of securities that collectively have an investment profile similar to that of the underlying index. Prior to September 23, 2019, the fund traded under the ticker IPE.