There are several issues private equity firms must consider when claiming compliance with the GIPS.  Most notable is that an internal rate of return must be presented as opposed to a time-weighted rate of return.  I encourage you to read the GIPS Guidance Statement on Private Equity, as it provides the mandates a private equity firm must meet to be GIPS compliant: http://www.gipsstandards.org/standards/guidance/archive/pdf/PrivateEquityGuidance.pdf