A free co-investment fee savings model in Excel, with a full worked case
The blended-cost bridge a co-investment programme actually buys, the NAV-years it carries against a primary commitment, the total-loss rate that erases the whole fee advantage, and the deal count that decides whether the programme survives its first write-off: seven sheets, one fictional plan, no macros.
The file models what a limited partner's co-investment programme actually saves against paying full fees on a primary allocation. At a 15% co-investment budget, the blended cost of a $1.5 billion private markets portfolio falls from 2.54% of net asset value to 2.17%, a saving of 37 basis points, about $4.4 million a year. That saving is worth a 22.8% total-loss rate on the co-invested capital before it disappears, but the budget and the per-deal cap fund only 2.7 deals a year, when at least 4.4 are needed to survive a single total loss. Every one of those numbers is a formula you can move.
Download the template
One Excel file, no macros, nothing locked. No account, no email address.
Seven sheets, in the order the argument runs. Amber cells are inputs; grey cells are formulas.
0. Read Me
What the file argues, and what it closes: the book asserts a co-investment programme "of any scale" lowers the blended cost of the portfolio, and never computes it.
1. The Inputs
Every figure used, each one pointing at the chapter or table it is drawn from.
2. NAV-Years
The multiplier a co-investment carries against a primary commitment, because it draws in full at close instead of over five years.
3. The Blended Cost
The saving at six programme sizes, from 0% to 50% of commitments in co-investment.
4. The Break-Even
The total-loss rate on co-invested capital that erases the whole fee advantage.
5. Deal Count
How many deals a year the budget and the per-deal cap actually fund, against how many are needed to survive a loss.
6. The Collision
What the extra NAV-years do to the commitment budget solved for elsewhere in the book, at five different co-investment hold periods.
7. Checks
The 22 figures the appendix prints, set against the cell that computes each one.
What the worked case shows
Measure
Value
Blended cost, no co-investment
2.54% of NAV
Blended cost at a 15% co-investment budget
2.17% of NAV
The saving
37bp ($4.4m/yr)
Break-even total-loss rate on co-invested capital
22.8%
Deals a year the budget and cap fund
2.7
Deals a year needed to survive one total loss
4.4
NAV-years carried per co-invested dollar
7.73x (vs 6.30x primary)
Read the last three lines together. The fee saving survives a 22.8% loss rate on co-invested capital, but a 15% budget and a per-deal cap of a third of a fund commitment fund only 2.7 deals a year: one write-off is more than a third of the year's cohort, well past the break-even. The binding constraint is not the budget or the cap on its own, it is deal count. Cutting the per-deal cap to about a fifth of a fund commitment, instead of a third, raises deal count to a survivable level on the same budget.
How to use it on your own programme
Open "1. The Inputs" and overwrite the amber cells: plan size, fund multiples, the average commitment, the per-deal cap and the budget share.
Read "3. The Blended Cost" first: it is the whole answer to whether the programme is worth building at any given size.
Check "4. The Break-Even" against your own loss experience on single-asset exposure before sizing the programme.
Use "5. Deal Count" to set the per-deal cap: the binding constraint is usually deals per year, not the budget.
Run "6. The Collision" alongside a primary pacing model: a co-investment carries more NAV per dollar and can push a portfolio over its target without a single new decision.
Keep the Checks sheet: once you change an input it stops matching the appendix, which is expected. Use its structure for your own tie-outs.
Questions people ask about it
Is this co-investment fee savings model really free?
Yes. It is a companion file to a book. There is no sign-up, no email address and no paid version.
Does it use macros or circular references?
No macros and no circular reference: the blended cost, the break-even and the deal count each build from inputs and earlier cells, never from their own result. The file recalculates in Excel, LibreOffice or Google Sheets without iterative calculation.
Why does a co-investment carry more NAV-years than a primary commitment of the same size?
A primary fund draws capital over about five years and starts distributing before it has finished drawing, so the average dollar is invested for less than the hold period. A co-investment is drawn in full on day one and held to exit: 7.73 NAV-years per dollar against 6.30 for a primary, 23% more net asset value carried for the same commitment.
Can I use it for a real co-investment programme?
You can reuse the structure: the blended-cost bridge, the break-even and the deal-count arithmetic. The plan, the fund terms and the figures in it are illustrative, and nothing here is investment advice.
The rest of the files
This template is one of the companion files for The Private Markets Limited Partner: the full set adds
the blank reusable model set, forty practice questions, three worked cases and the working documents behind them. Free, like this one.