Private equity investor Apollo Investment may not take businesses to the moon, but it does provide some of that cheese to help them soar. A business development company (BDC) and closed-end investment fund, it specializes in subordinated debt and equity capital investments, providing middle-market companies ($50 million to $2 billion in revenues) with mezzanine or senior subordinated loans. It also makes direct equity investments. The company, which typically invests between $20 million and $250 million per transaction, has stakes in about 70 companies in the US and western Europe, including financial services behemoth First Data, technology insurer Asurion, and human resources outsourcer Ceridian.