Why XIRR Breaks When Your Angel Portfolio Hits 10+ Investments

Why XIRR Breaks When Your Angel Portfolio Hits 10+ Investments Excel's XIRR function works perfectly for your first few deals: Investment: -$25,000 on 2024-01-15 Current value: $75,000 on 2026-04-10 XIRR: 44.2% annualized return But as your portfolio grows to 10, 15, 25+ investments, something breaks. You can calculate XIRR for individual companies, but you can't get a portfolio-level XIRR . The cashflow schema that works for single investments becomes impossible at the portfolio level. Here's why — and what to do about it. How Most Angels Organize Their Spreadsheets (The Wrong Way) Most angel tracking spreadsheets are organized by company — one row per investment: Company A $25K 01/15/24 $75K 3.0x MOIC 44.2% XIRR Company B $50K 03/10/24 $45K 0.9x MOIC -23.1% XIRR Company C $25K 06/20/24 $25K 1.0x MOIC 0.0% XIRR This structure makes it trivial to calculate XIRR for each individual investment using Excel's =XIRR(values, dates) function. But it makes portfolio-level XIRR impossible . Why