Build your own property underwriting models in Excel with an agent
Idea + starter prompt, not run by us yet
For: Property developers who pay analysts to build deal models
A solo commercial property developer swapped outside Argus analysts for Excel underwriting models with Claude Code. His first model was a DCF for an industrial building with one tenant. He then grew to multi tenant and was adapting it for retail, covering rent rolls, reimbursements, downtime, renewals, fit-out costs, commissions, debt, exits and sensitivities. He says models now take minutes, not hours or days.
Steps
- Start with one simple deal type you know well.
- List every input your current model uses, such as rents, downtime and debt terms.
- Ask Claude Code to build the model in Excel with formulas you can see.
- Check its numbers against a deal you already underwrote another way.
- Use your own underwriting judgment to validate every assumption, since the source gives little detail.
Starter prompt
Build an Excel underwriting model for a [property type] deal. Inputs: [rent roll, lease terms, downtime, renewal odds, fit-out costs, commissions, debt terms, exit cap rate]. Use visible formulas, one input sheet and clear labels. Add a sensitivity table for [variables]. Test it with these sample numbers: [sample deal] and show me the results. Do not hide any calculation in macros.
Original post: Reddit · found via agentusecases.ai. Written up in our own words. We haven't run it, so test it on made-up data first.