SPTL invests across the entire long-term US Treasury spectrum (10 years and longer), excluding inflation-protected bonds. Its long effective duration, weighted average maturity and yield-to-maturity naturally exposes investors to higher interest rate risk, but not any more than is marketlike. 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. The fund changed ticker symbols from TLO in Oct. 2017. Prior to Oct. 31, 2025, the fund did not use the State Street brand reference in the fund name.