Some of the hottest private companies could go public before the end of the year, like fitness chain SoulCycle and mobile payments processor Square. ‘Everyone is looking at SoulCycle - that’s a growth company,’ said Kathleen Smith, principal of Greenwich, Conn.-based Renaissance Capital, which manages the Renaissance IPO ETF (IPO). ‘We think SoulCycle is targeting for later this year and could have debuted after Labor Day, but I think decided to wait for some of the turbulence in the market to subside.’ She said Square, the mobile payments company run by Twitter (TWTR) co-founder Jack Dorsey, is expected to debut as a public company later this year. This week, Richmond, Va.-based food distributor Performance Food Group and Nashville-based surgical hospital operator Surgery Partners are set to go public, raising upwards of $350 million each. Only three IPOs have priced in September, the lowest level since 2011, Smith said. While some big names are expected to go public towards the end of 2015, the market is still on rocky footing. Activity is down 31 percent so far this year, compared to the same time last year, Renaissance said. TheStreet’s Scott Gamm reports from New York.