This article from the CFA Institute Website discusses performance metrics such as Total Value to Paid in Multiple (TVPI) and Internal Rate of Return (IRR), but the author fails to recognize opportunity costs. If a PE fund is using temporary leverage to delay capital calls, it provides investors with an opportunity to earn a return on their capital during the "deferral period." That return should be considered when evaluating the investment performance of the fund.
Subscription lines of credit can influence a fund’s IRR profile as well. In this type of leverage, one or more lenders provide a fund with revolving credit facility. It is collateralized by a pledge of the right to call and receive capital contributions from the fund’s investors.