Why this exists

A portfolio company raises at a higher price. How long until the fund understands what it owns? Most GPs reach for Excel. Cap table math is deterministic. Spreadsheet ops are not.

The problem is friction

Ownership tracking, waterfall computation, and fund MOIC analysis are repetitive and rule-bound. They should be checkable and private. Instead, the work usually sits in fragile workbooks that:

• Break when a shareholder is added
• Force hand recalculation when terms change
• Live on a laptop — or in Slack
• Have to be rebuilt when the round is a down round
• Leave doubt that the math is right

Speed matters on a call. Mistakes are expensive. Privacy matters when the file is a live deal. Scenarios multiply — one exit becomes five — and each one is more manual work.

What CapStack is

CapStack GP is a browser scenario model for venture GPs: exit waterfalls, ownership dilution through rounds, and fund-level MOIC. Assumptions, holders, rounds, convertibles, and exit cases go in; the engine computes proceeds, dilution, and fund economics, and can produce BLUF text for an IC memo.

No account. No required backend. Deal data stays in the browser (localStorage) unless optional features are used. Export JSON to move a model; import it later. Close the tab.

It is a pre-decision calculator — not a cap table system of record, transfer agent, or portfolio admin platform. Carta, Pulley, and AngelList keep the books. This tool answers “what if.”

What it models today

• Seniority-stacked liquidation preferences; participating, non-participating, and capped participation
• Conversion elections with iteration; SAFE and note conversion into the exit waterfall
• Ownership through financing rounds, with a pro-rata toggle
• Gross/net MOIC, fees, hurdle, and carry using European waterfall math only
• Anti-dilution with a global default, optional per-holder override, and round carve-outs
• Forty-seven assumptions across six domains; waterfall curve; BLUF copy; undo; print stylesheet

Known limits are stated in the FAQ: American (deal-by-deal) carry is out of scope; escrow is a per-holder holdback after prefs run on the full pot (not an NVCA second pass); some ceremony controls remain labeled Not modeled; cap-table FD% and waterfall claim% can differ and must be reconciled before a memo. Fund-level modeling (capital calls, J-curve, American waterfalls): ATLAS.

Publisher

CapStack GP publishes this model. Questions go through Send Feedback in the model. No account is required.

Who it is for

GPs, partners, and associates who need payout clarity before a board call, a term-sheet stress test, or an IC write-up. Founders can use it to understand their own stack. It is not LP reporting software and not multi-user cloud collaboration — share a JSON export or a printed BLUF.

Cost

The modeling app has no paywall, seats, or trial. Optional website embeds are a separate branding product. Normal modeling does not send the cap table to CapStack; see Privacy.

Not legal, tax, or investment advice. Sample data is fictional. Numbers are only as good as the inputs and the engine’s documented scope.