The deal lives in a spreadsheet. So does the mistake
Commercial real estate runs on Excel and has resisted every attempt to move it elsewhere, because every deal is bespoke. SheetAI works inside the model you already built: cleaning rent rolls, abstracting leases into rows, checking that your NOI actually reconciles, and writes standard formulas an investment committee can audit line by line.

Altus Group's CRE innovation research has consistently found spreadsheets remain the primary tool for valuation and underwriting, with data fragmentation cited as the sector's leading operational challenge. The models are bespoke, the inputs arrive as PDFs, and the checking is manual.
Source: Altus Group: CRE Innovation ResearchThis page is about the analytical work behind property transactions and management: comparable sales and rent analysis, rent roll normalisation, lease abstraction, acquisition underwriting, debt sizing, portfolio reporting, and the monthly owner statements that nobody enjoys producing. SheetAI reads the ranges in your model, writes standard Excel and Google Sheets formulas, and produces the checks that separate a defensible underwrite from an optimistic one. It does not value property, it does not give investment advice, and it is not a substitute for a qualified appraisal; the boundaries section is exact about that, because in this sector the difference between analysis and valuation is a regulated one.
The state of property analysis in 2026
Four realities that explain why the sector's most important decisions still get made in a workbook.
CRE firms citing spreadsheets as their primary valuation tool
Purpose-built platforms have made real inroads in portfolio management and reporting, but deal-level underwriting stays in Excel because every deal has a structure the platform did not anticipate.
Altus Group CRE surveysData fragmentation cited as a leading operational challenge
Rent rolls from the property manager, operating statements from the accountant, leases as PDFs, comps from a subscription service: four sources, four formats, one model.
Altus Group / industry surveysSpreadsheets containing at least one error
Audit studies across sectors converge on this figure. In underwriting, the error that matters is usually an input carried forward from the last deal rather than a broken formula.
EuSpRIGResidential transactions where pricing is set from comparables
Comparable analysis is the foundation of residential valuation, and the selection of which comparables to use is where judgement (and bias) enters.
Standard appraisal practiceThe pattern: the sector's core analytical work is document-to-model transcription and structured comparison: reading a lease into rows, reconciling a rent roll against an operating statement, checking a comp set for like-for-like. That is precisely the work an AI inside the spreadsheet can take on without asking anyone to abandon the model they trust.
Anatomy of an acquisition underwrite
Where the week actually goes on a mid-market commercial acquisition, before any of it is automated.
Phase 1: Assemble the data room
- ›Rent roll from the property manager
- ›Trailing 12 operating statements
- ›Lease PDFs, service charge budgets, capex history
Phase 2: Normalise the rent roll
- ›Standardise unit references and tenant names
- ›Convert rents to a common basis and period
- ›Flag vacancies, holdovers, and expiring terms
Phase 3: Abstract the leases
- ›Term, commencement, expiry, break options
- ›Rent steps, reviews, and indexation
- ›Recovery structure, caps, and exclusions
Phase 4: Build and stress the model
- ›NOI build-up from the normalised roll
- ›Debt sizing against DSCR and LTV covenants
- ›Sensitivity on exit yield, rent growth, and vacancy
Phase 5: Package for committee
- ›Summary metrics, comp set, and risk register
- ›Reconcile every headline number to source
- ›Answer the question about cell F212
One input, carried forward
In 2012 the London Whale losses at JPMorgan ran past $6 billion, and the bank's own task force report traced part of the failure to a value-at-risk model implemented across spreadsheets where an analyst copied and pasted data between worksheets by hand. One operational error (dividing by a sum where an average was intended) understated the modelled risk by roughly half. The individual mistake was trivial. What made it consequential was that the model had been rolled forward, trusted, and never independently re-derived.
The lesson: Every underwriting model in this sector is a copy of a previous one, which means every assumption in it has a provenance nobody has checked since the deal it came from. The practical defence is to make the model state its own inputs: where each number came from, which are hardcoded, which are linked, and which changed since the last version. SheetAI will produce exactly that audit: listing hardcoded values inside formula ranges, flagging inputs that differ from the source documents, and reconciling the headline metrics back to the rent roll.
Source: JPMorgan Chase: Report of the Management Task Force Regarding 2012 CIO LossesWho it's for
If your deal, your portfolio, or your month-end lives in a workbook, this is the page.
CRE Acquisition Analysts
Rebuild an underwriting model per deal under a deadline, inheriting the last one's assumptions.
Property Managers
Produce owner statements and rent rolls monthly across a portfolio of assets and systems.
Residential Agents & Teams
Assemble comparable analyses per instruction, by hand, from a subscription export.
Asset Managers
Track lease events, break options, and expiries across hundreds of tenancies in a spreadsheet.
Investors & Syndicators
Need a defensible model and an investor pack that ties back to source documents.
Real property workflows
The prompt, what the agent does with your model, and the state it leaves it in.
- ✓Normalises unit and tenant identifiers so the two sources join.
- ✓Converts rents onto a common annual basis regardless of how each line was stated.
- ✓Reconciles the totals and computes line-level variances.
- ✓Characterises each material difference: vacancy timing, rent free, holdover, arrears.
Rent roll normalised across 84 units and reconciled to within £900 of the T12. Six differences explained, two flagged as unexplained, both of which turned out to be side letters absent from the data room.
Everything property teams need, inside the model they already use
Rent roll normalisation, lease abstraction with provenance, comp screening with documented exclusions, and a model audit before anything reaches committee.
Plays well with your stack
- Yardi and MRI exports
- AppFolio and Buildium reports
- Argus cash-flow exports
- MLS and portal comparable downloads
- Lease PDFs and data-room documents
- Accounting exports (Xero, QuickBooks, Sage)
What one acquisition underwrite looks like
A representative mid-market commercial acquisition (84 units, 14 leases in the data room) before and after the transcription and checking move into the sheet.
Before SheetAI
~52 hours- MonAssemble the data room; reconcile four incompatible formats~9h
- TueNormalise the rent roll; chase why it does not tie to the T12~11h
- WedAbstract 14 leases by hand into the tracker~12h
- ThuBuild the NOI, size the debt, run sensitivities manually~11h
- FriPackage for committee; re-derive the numbers under challenge~9h
With SheetAI
~14 hours- MonRent roll normalised and reconciled; variances explained~3h
- TueLeases abstracted with provenance; REVIEW items to counsel~3h
- WedNOI and debt sizing built; sensitivity grid generated~3h
- ThuModel audited; 31 findings cleared before committee~3h
- FriPack assembled with every number traced to source~2h
~73% reduction on a representative 84-unit acquisition underwrite.
What SheetAI will not do
Property is a sector where analysis and valuation are legally distinct activities. The line is worth stating precisely.
Value a property
Producing a formal valuation is a regulated professional activity under RICS Red Book standards in the UK, USPAP in the US, and comparable regimes elsewhere. SheetAI computes comparables, ratios, and cash flows from inputs you supply. It does not opine on market value, and no output from it should be represented as a valuation to a lender, a court, or an investor.
Give investment advice
It will not tell you whether to buy, at what price, or on what terms. It builds and checks the analysis that informs that judgement. Where a recommendation constitutes regulated financial advice, it belongs with someone authorised to give it.
Interpret a lease as a lawyer would
It abstracts commercial terms into rows and flags ambiguity rather than resolving it. Whether a break notice was validly served, whether a review mechanism is upward-only in effect as well as in drafting, and what a poorly drafted recovery clause actually means are legal questions. The REVIEW flags exist precisely so those reach a solicitor.
Replace due diligence
It reconciles what is in the data room. It cannot tell you what is missing from it: the side letter that was never uploaded, the dispute nobody disclosed, the structural survey that has not been commissioned. Reconciliation is not diligence, and the gap between them is where deals go wrong.
The lease abstraction used to be a full day per deal and it was the part I trusted least, because you are reading fourteen documents at nine at night. Now the terms land in the tracker with a page reference and the ambiguous ones are flagged. We found a break option in the second deal we ran it on that had been missed in the original underwrite.
Frequently asked
What property professionals ask before they let a model near a live deal.
Can it value a property?
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Will it work with my existing underwriting model?
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How well does lease abstraction work?
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Can it pull comparables for me?
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Does it handle service charges and recoveries?
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Is my deal data confidential?
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Can it audit a model I inherited?
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Does it work for residential as well as commercial?
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Sources & further reading
Every benchmark and statistic on this page is drawn from publicly available research. We cite our sources because we read theirs.
- Altus Group: CRE Innovation and Technology Research↗
Recurring industry research finding spreadsheets remain the primary valuation and underwriting environment in commercial real estate, with data fragmentation ranked among the leading operational challenges.
- RICS: Valuation Global Standards (Red Book)↗
The professional standard governing formal valuation in the UK and internationally; defines why comparable analysis and valuation are distinct activities.
- The Appraisal Foundation: USPAP↗
US uniform standards of professional appraisal practice; the equivalent regulatory boundary for property valuation in the United States.
- JPMorgan Chase: 2012 CIO Losses Task Force Report↗
Documents how a rolled-forward spreadsheet model with manual data transfer produced a material understatement of risk; the canonical case for auditing inherited models.
- EuSpRIG: Spreadsheet Risk Research↗
Ongoing collection of documented spreadsheet failures; the ~90% error rate finding and numerous property and finance sector cases.
- National Association of Realtors: Research and Statistics↗
Residential transaction data and practice research, including the central role of comparable analysis in pricing decisions.
Related teams using SheetAI
Adjacent functions that hit the same kinds of problems.
Stop rebuilding the model.
Start checking it.
Open your underwriting workbook and ask for an audit. You will have the hardcodes, the broken patterns, and the carried-forward assumptions listed before your coffee goes cold.
Pay as you go, no subscription required