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PropRate

118 Tremont St, Unit 4

Boston, MA

Market estimate
3.50%4.30%

Blended condo cap rates, Beacon Hill / Downtown Boston submarket. An estimate, not a measured NOI.

An estimate from other people's numbers — the cap-rate equivalent of a Zestimate. Cited, not verified.
Market estimate (ATTOM / CompStak submarket feed)
PropRate
2.36%

$20,760 NOI ÷ $880,000 appraised value.

96% of gross income is a signed lease attested on the chain — not an assumed market rent. A number you can underwrite against.

Underwrite it yourself

Slide any assumption — the cap rate recomputes live.

Verified on the chainIn-place annual rent$50,400
Market estimateVacancy4%

Operating expenses

Public record — citedProperty tax$8,900
Market estimateHeating & utilities (owner-paid)optimizable$7,200
Verified on the chainCondo association fee$4,800
Market estimateInsurance$1,400
Market estimateManagement (6%)$3,024
Market estimateMaintenance & reserves$2,300
Net operating income$20,760
Cap rate2.36%
The Built World loop

Heating & utilities (owner-paid) is your biggest controllable cost — dragging the cap rate by 82 bps. A high-efficiency heat-pump retrofit (Mass Save eligible) could cut it ~55% — lifting PropRate to 2.81% (+45 bps).

No other underwriting tool can do the next part: route the fix to a verified maker on the graph who can bid it. The cap rate doesn't just flag the problem — it convenes the person who solves it.

A bid accepted here becomes a verified working relationship on the chain — and the retrofit it produces becomes the next capital improvement the market number can't see. The loop closes on itself.

What the market number can't see

Capital improvements verified on the chain — the reason the income holds.

Zillow gives you an AVM. Steve wanted a cap rate you could trust. The market quotes 3.90% from numbers nobody verified. PropRate is 2.36%— built from a signed lease and a permitted, signed-off renovation on the Propreti chain. Same property. One number is an estimate. The other has its receipts attached.

PropRate — named for Steve. Wall Street real-estate banker, then Auldbrass Partners. He said the data would be there one day. It is.

Prototype note: the market estimate is realistic seeded data standing in for a live provider feed (ATTOM / Reonomy / CompStak). The cap-rate math is real and computed live from the inputs above. The verified income and any accepted bid become durable at the persistence backend milestone.