This ETF is one of several ETFs available that offers exposure to mid cap U.S. stocks, an asset class that can make up a significant portion of long-term, buy-and-hold portfolios. As such, this ETF may be more appealing to those in the portfolio construction process as opposed to short term traders. Mid cap stocks are appealing to many because they still have significant growth potential but they are less risky than their small and micro cap brethren. IVOO offers exposure to a balanced portfolio of stocks, including close to 400 individual names and spreading exposure relatively evenly. The expense ratio is among the cheapest in the category making it an excellent choice for those looking to keep costs to an absolute minimum. For those seeking other options in the space similar choices can be found in the MDY and IJH funds, the ultra-cheap FMM, and equal-weighted EWRM.