The fund provides broad exposure to the largest US growth companies. The index is considered a gauge of overall growth stock returns in the United States. Growth stocks are specifically selected from the S&P 500, its parent index. Stocks are selected based on three growth factors: sales growth, the ratio of earnings change to price, and momentum. Eligible securities should also meet certain liquidity and size requirements and have positive reported earnings in the most recent quarters. At times, given the limited number of holdings to reflect sector representation, securities meeting these criteria do not guarantee automatic index inclusion. The index is weighted by market capitalization and rebalances every December.