Midstream energy assets and companies have been a major target of PE firms since large companies began spinning them off at a high rate earlier in the decade. In the past two and half years alone, private equity firms have invested in 89 midstream assets and companies, according to the PitchBook Platform. However, the collapse of energy prices and the current credit situation have almost put a complete stop to investing in the sector this year -- only five midstream deals have been completed. This figure pales in comparison to that of the gangbuster year of 2007, during which 51 midstream investments were completed. Active investors in midstream assets include Riverstone Holdings, ArcLight Capital Partners and Quintana Capital Group.