Private equity giants like Apollo and Blackstone are eyeing insurance as their next big disruption of Wall Street. : Private equity moguls Leon Black of Apollo Global and Stephen Schwarzman of Blackstone Group are likely to solve a brewing liability crisis way before they get their hands on the American 401k retirement system. That's the takeaway from Apollo and Blackstone's somewhat unheralded push into the insurance market, a move that's likely to be a major growth driver for both heavyweight firms in 2018.