PHB invests in high-yield corporate bonds rated at Ba1/BB+ or lower but not below B3/B- by Moody's or S&P. The starting universe begins with all US-based publicly traded corporations that are scored by RAFI using four fundamental factors: book value of assets, gross sales, gross dividends, and cash flow. Only companies with positive scores are selected. There are two distinct maturity cells (15 years and 510 years) that the index employs, which allow up to two bonds per issuer. The issues are weighted proportionally to a companys RAFI score. The RAFI-patented fundamental weighting scheme normally results in overweighting of higher-quality bonds. The index is reconstituted monthly and rebalanced annually for new RAFI scores.