State Street SPDR S&P MIDCAP 400 ETF Trust(AMEX:MDY)

MDY, as one of the first ETFs to launch in the US, the fund offers extremely liquid exposure to a popular mid-cap index. It is one of several funds tracking the S&P mid-cap 400 Index. Unlike most competitors, MDY uses the unit investment trust structure, which requires a direct replication of its underlying index and doesn`t allow for reinvesting dividends between distribution dates or for lending out securities. While this older legal structure is perfectly serviceable, it hinders the fund`s tracking in comparison to competitors. Although the fund bills itself as mid-caps only, in comparison to our large-leaning benchmark it includes a small-cap tilt causing a lower average market cap. Still, the fund is a good representation of its segment of the market, taking no significant sector bets and avoiding concentrated holdings. While very long-term investors might prefer peer funds, MDY is a solid and extremely popular choice in the mid-cap space.