IJH tracks the S&P MidCap 400, which holds about 400 US mid-cap companies chosen by an index committee using size, liquidity and profitability criteria. Mid-caps are usually more established than small caps and have more room to grow than the largest companies. The sector mix is more balanced than in large-cap indexes, with larger weights in industrials, financials and consumer companies and a smaller weight in mega-cap technology. Because of the profitability screen, companies with recent losses are excluded. IJH is commonly used to fill the mid-cap segment of a portfolio.