The California Public Employees Retirement System (CalPERS) has the nation's largest private equity portfolio, and recently updated fund-by-fund performance data on its website. These are the numbers by which PE investors really are judged, so I figured it was worth a quick look to see the five best -- and five worst -- performing funds within the CalPERS portfolio.

    Because private equity is a long-term asset class characterized by J-curvature, I've excluded all funds raised between 2007 and 2010. The relevant metric is net IRR. All data is through March 31. Here goes:

    THE BEST:

    1. Clearstone Venture Partners 1-B (1999): 154.7%

    2. T3 Partners II (2001): 95.6%

    3. GCP California Fund (2003): 91.9%

    4. WLR Recovery Fund II (2002): 79.5%

    5. Permira Europe I (1997): 74.5%

    THE WORST

    1. Aberdare II Annex Fund (2006): -46.6%

    2. Exxel Capital Partners V (1998): -41.7%

    3. Opportunity Capital Partners IV: -28.9%

    4. Convergence Ventures II (1999): -28.5%

    5. Richardson Capital Private Equity 2 (2006): -28.1%