The listing says 8% cap. The seller’s spreadsheet shows fat cash flow. You tour the house, it “feels like a good one,” and you offer.

That is not underwriting.

Underwriting is rebuilding the file yourself:

• In-place rent, not pro forma rent

• Taxes after reassessment, not the current bill

• Insurance you actually quoted

• Vacancy and capex that exist in the real world

• A downside case where rent is wrong by 10%

If the deal only works when every assumption is friendly, you are buying hope at a premium.

I built Yield Lab around that gap — teach people to kill bad deals fast so they only chase yield they can defend.

If you have a listing on your desk right now, run those five checks before you call the agent back.