The bear-market rank details how an investment has performed during bear markets. Morningstar adds performance during each bear-market month to reach a total bear-market return. Based on these returns, a percentile rank is assigned within a group (stock funds, bond funds, etc). The highest (or most favorable) percentile rank is 1 and the lowest (or least favorable) percentile rank is 100. For stock funds, a bear market is defined as all months in the past five years that the S&P 500 lost more than 3%; for bond funds, it's all months in the past five years that the Barclays Aggregate Bond index lost more than 1%. Stock funds are ranked separately from bond funds.