By Benjamin RobertsonSuperstar private equity firms have lost their edge, according to a new long-term study.Investing in buyout funds with top track records used to come with an above average chance that future returns would outstrip peers. That theory no longer stands, with first time funds performing just as well, said the study, published by the U.S. National Bureau of Economic Research and using data from about 2,200 funds over three decades.Prior to 2001, more than a third of managers ranked among the top 25% of performers at the time of fund raising went on to score market-leading returns in their next fund. Since the start of the century, top managers only had around a one-in-four probability of repeating their performance, which is “pretty much random”, co-author Tim Jenkinson said. The report doesn’t identify any firms.“It tells you it is hard to repeat top quartile performance and investors should look at broader metrics,” Jenkinson said by phone.That matters for the private equity investors, including pension funds, endowments and sovereign wealth funds, who have poured trillions of dollars into the asset class in recent years. Past performance, including quartile rankings, is an important metric for investors to decide to commit to new funds, given capital is locked away for upwards of half a decade.“A lot of investors say we need to have a track record before we can invest, but if you invested in first-time funds across the board you did pretty well,” said Jenkinson, a finance professor at the University of Oxford’s Said Business School.On average, the study found that first-time funds returned 1.93 times their multiple of invested capital, a commonly used performance metric, Jenkinson said. This put them on par with top quartile buyout funds run by established managers.Returns for existing buyout and first-time funds continued to exceed those of public markets as measured by the S&P 500, the study said. The report’s other authors are Robert Harris, Steven Kaplan and Ruediger Stucke.