SPLB attempts to capture the US long-term, investment-grade corporate bond market in ETF form. The funds underlying index invests strictly in US dollar-denominated issues, predominantly from US firms which have a remaining maturity of at least 10 years. The fund uses a simple strategy, selecting and weighting constituents by market value. The fund also uses a sampling method in tracking the index, meaning it invests in securities that have identical characteristics of the securities that comprise the index. The index is rebalanced monthly, on the last business day of the month. The fund ticker changed from LWC in Oct. 2017.