Launched on November 8, 2005, the State Street SPDR Portfolio S&P 400 Mid Cap ETF (SPMD) is a passively managed exchange traded fund designed to provide a broad exposure to the Mid Cap Blend segment of the US equity market.The fund is sponsored by State Street Investment Management. It has amassed assets over $15.07 billion, making it one of the larger ETFs attempting to match the Mid Cap Blend segment of the US equity market.Why Mid Cap BlendWith market capitalization between$2 billion and $10 billion, mi ...