SPTB is a passively managed fund offering market-like exposure to the US Treasury space. The index is a broad, vanilla basket of US Treasury securities with at least one year to maturity, an investment-grade rating, and a minimum outstanding face value of $300 million. It specifically excludes bonds like TIPS and floating-rate notes. To be included in the index, securities must be USD-denominated, fixed-rate, and non-convertible. The fund may also hold non-index securities, cash and cash equivalents, or money market instruments for cash management purposes. The index is market capitalization-weighted and is reconstituted and rebalanced on the last business day of each month.