A Crucial Enhancement to the Takahashi–Alexander Cash Flow Model

The Takahashi and Alexander (TA) model is a widely used framework for simulating private equity cash flows. However, its core shape parameter <italic>b</italic>—which governs the distribution timing—lacks a direct connection to investor-relevant metrics such as internal rate of return (IRR) and total value to paid-in capital (TVPI). This article introduces a reformulation of the TA model that replaces the opaque <italic>b</italic>-parameter with a more intuitive and analytically derived function of the investor’s performance goals. We define a dimensionless <italic>duration fraction</italic> <inline-formula><inline-graphic></inline-graphic></inline-formula>, where <italic>M</italic> is the desired TVPI, <italic>G</italic> the target IRR, and <italic>L</italic>, the fund’s life. We then derive the relationship <inline-formula><inline-graphic></inline-graphic></inline-formula>, offering a closed-form link between fund performance objectives and the TA model’s cash flow shape. This formulation simplifies calibration, enhances interpretability, and enables goal-driven simulation of capital calls and distributions. Numerical validation confirms the robustness of the approximation across a wide range of practical scenarios, making the TA model significantly more accessible and aligned with real-world decision-making.