Designed to provide broad exposure to the Mid Cap Value segment of the US equity market, the Invesco S&P MidCap 400 Revenue ETF (RWK) is a passively managed exchange traded fund launched on February 22, 2008.The fund is sponsored by Invesco. It has amassed assets over $854.70 million, making it one of the average sized ETFs attempting to match the Mid Cap Value segment of the US equity market.Why Mid Cap ValueWith market capitalization between$2 billion and $10 billion, mid cap companies usually contain hi ...