PWZ focuses on AMT-free bonds primarily within the California municipal debt market but includes small amounts in US territories such as Puerto Rico and Guam muni issues as they currently enjoy the same tax treatment as California munis. The index selects US-denominated investment-grade tax-exempt debt securities that have at least 15 years remaining term to maturity. The fund may carry more interest rate risk due to the skew towards long-dated bonds. The fund also tilts heavily toward the volatile revenue bond sector. These biases boost the funds yield, but also increase risk. The fund and the index are rebalanced and reconstituted monthly.