Keep two versions of NOI

Keep the seller's historical NOI beside your acquisition case. When AI rewrites the operating statement, I want to see every adjustment that crosses from one column to the other.

- Sasha Deneux

The Take: An updated assumption should leave the history intact

The OCC's Commercial Real Estate Lending handbook, published in March 2022, treats property cash flow as central to CRE lending analysis. For an acquisition team using AI, the practical question is whether the output makes clear which cash flow it describes.

Ask an assistant to normalize a T-12 and it may combine historical expenses with a buyer's estimate of future taxes or insurance. Each input might be reasonable on its own. The result still needs a clear label explaining what it represents.

I want the workflow to preserve the seller's operating history, then show the acquisition adjustments separately. That makes it possible to disagree about an assumption without losing the underlying record. It also gives the reviewer somewhere to put a question that remains unanswered.

Financing needs the same discipline. A lender's quote has its own date, structure, spread, covenants, and conditions. A market headline does not supply those terms. Keep the quote with the assumption, and show which case uses it.

An underwriting refresh should leave a trail: what changed, why it changed, the supporting document, and who accepted it. The team can then decide whether the new information changes its view of the deal.

Faster scenario generation is useful when each scenario has that trail. Otherwise, the next meeting begins with people trying to reconstruct which version they are discussing. Keep both columns visible: the property as reported and the acquisition case your team is proposing.

The Teardown: Build a bridge from historical to adjusted NOI

Start with a saved copy of the operating statement and a separate assumptions sheet. Keep both attached to the deal record. Don't let a generated narrative become the only place an adjustment is explained.

Reproduce the reported period. Have the workflow identify the statement's start and end dates, its income and expense categories, and any subtotals. Preserve missing values as missing. Ask the analyst to reconcile material totals to the source before making acquisition adjustments.

Write down what each income line includes. Collected rent, scheduled rent, concessions, bad debt, and reimbursements can appear in different arrangements. If collected rent is already net of concessions, deducting the same concession again changes the reported result. A label alone may not settle this; the reviewer may need the rent roll or supporting ledger.

Create an adjustment register. Each row needs the historical amount, proposed adjustment, basis, date, owner, and status. A tax estimate can stay provisional while the team obtains better support. A current insurance quote can replace an earlier assumption without overwriting what the property paid historically.

Keep calculations reproducible. Use the workbook's formulas for the resulting NOI and debt coverage. Compare the generated narrative against those approved cells. If the financing quote changes, update the assumption and recompute the scenario before refreshing the prose.

Review the differences. The useful output is a short list of changes and unresolved items. Which expenses explain the gap? Which assumptions materially affect coverage? What evidence is still needed before the deal advances?

Try the process on a deal your team already understands. Include one deliberately ambiguous income label and one outdated assumption. Check whether the workflow preserves the ambiguity and identifies the stale input, then inspect material values that received no warning. That gives you a more informative trial than an immaculate demonstration file.

The multifamily underwriting walkthrough shows the sequence with an illustrative example. Use the same saved example when evaluating a vendor so the comparison reflects your team’s documents and review requirements.

Signal

Reference desk: sources to keep beside the underwriting review.

• March 2022: examine the property cash flow. The OCC's CRE lending handbook covers property analysis and repayment risk. Use it as background for questions about the operating statement, then document the assumptions specific to your acquisition. It is written for bank supervision, not as a ready-made buyer model.
• July 2024: a generated number needs a checked source. NIST's generative AI profile calls for source verification. In a T-12 review, inspect the period and line item behind each material value, including values the workflow did not flag.
• January 2023: preserve the evaluation record. NIST's AI Risk Management Framework includes documenting test sets and measures. Save the same practice deal, expected adjustments, and review results so the next model or vendor faces a comparable test.

From NextAutomation

We build underwriting workflows around a team's source documents, existing model, and review process. Book a conversation with one example of where those handoffs break. The model-builder resource pack is a starting point for organizing the work.

Keep the history intact. Make the assumptions easy to challenge.

Next edition: what an IC memo should carry forward when the model changes.

- NextAutomation Team