More evidence that privately owned firms do better:

We present evidence on the performance of nearly 1400 U.S. private equity (buyout and venture capital) funds using a new research-quality dataset. … Average U.S. buyout fund performance has exceeded that of public markets for most vintages for a long period of time. The outperformance versus the S&P 500 averages 20% to 27% over the life of the fund and more than 3% per year. Average U.S. venture capital funds, on the other hand, outperformed public equities in the 1990s, but have underperformed public equities in the 2000s. … Within a given vintage year, performance relative to public markets can be predicted well by a fund’s multiple of invested capital and internal rates of return. (more)