Miami-Dade commercial real estate is a structurally peculiar data environment. The market has grown rapidly as institutional capital from domestic and international sources increased allocations to South Florida, but the data infrastructure has not kept pace. Commercial brokerages report heavily on the office and industrial segments, but significant transaction volume — particularly in the sub-$25M multifamily and mixed-use segments — occurs off-market, is minimally publicized, and often involves entities that are not identifiable as institutional buyers from the public record.
This piece documents the specific data gaps we encountered in Miami commercial deal analysis and how we built around them. The central argument: CoStar comp data, while useful, systematically underrepresents the Miami transaction market in ways that matter for accurate valuation. Relying on it as a sole data source produces comp pools that are smaller and less representative than the underlying market warrants.
The Off-Market Transaction Problem in Miami
Miami commercial transaction markets have always had a higher-than-average off-market component. Buyers include international family offices, domestic private equity with direct relationships to brokers, and owner-operators who transact through personal relationships rather than open-market processes. Broker-reported transaction databases, which depend on brokerage participation for data contribution, capture a lower share of total Miami transaction volume than they do in institutional markets like New York, Chicago, or Dallas where large REIT and institutional buyer dominance drives higher reporting rates.
Our analysis of Miami-Dade county deed records for commercial transactions in the $3M-$25M range over a 24-month period through Q3 2024 found that broker-reported databases (including CoStar) captured approximately 62-68% of transactions by count and 70-75% by dollar volume. The gap — representing 25-35% of transactions by count — consists predominantly of off-market deals where the transaction was not publicly marketed through a brokerage and therefore was not reported to commercial data aggregators.
Off-market transactions in Miami-Dade commercial real estate are not an anomaly — they are a structural feature of a market where relationship-driven capital represents a disproportionate share of buyers. A comp pool that excludes them is systematically incomplete.
What the County Deed Record Reveals That CoStar Does Not
Miami-Dade county recorder filings are public record and available in near-real-time. Every deed transfer, regardless of whether it was brokered through a reporting brokerage, appears in the county record. This includes:
- Deed transfers showing grantee and grantor, parcel ID, and recorded consideration (sale price)
- Mortgage recordings, revealing the loan amount and lender at the time of acquisition
- Documentary stamp tax amounts, which can be used to back-calculate transaction price where the deed consideration is stated only as "ten dollars and other good and valuable consideration"
The county deed record does not contain cap rate, NOI, or lease information. It is a price-only data source. To construct a useful cap rate comp from a county deed transaction, you need to combine the price from the deed record with an estimate of the property's income at the time of sale — which requires either CMBS servicer data (for encumbered properties) or submarket rent and vacancy benchmarks from independent data sources.
This is the core of our Miami data architecture: ingest the full deed record universe first, then enrich the subset of transactions that have available income data. The result is a comp pool that is 30-40% larger than what broker-reported sources provide for the Miami market, with the added transactions concentrated in the off-market and smaller-transaction segments.
The Sub-$25M Multifamily Segment Is the Largest Gap
The data gap is most pronounced in the sub-$25M multifamily segment, which includes garden-style apartment communities, small-to-mid-size multifamily properties in Edgewater, Wynwood, Little Haiti, and the western neighborhoods of Miami-Dade, and NNN multifamily land parcels. This segment transacts frequently and in relatively high volume for Miami, but the buyer universe skews heavily toward private operators, family offices, and international capital — all groups that transact off-market with higher frequency than institutional REIT buyers.
For an underwriter evaluating a 48-unit garden multifamily asset in Little Haiti, a CoStar-sourced comp pool might yield 6-8 comparable transactions in the most recent 24 months within reasonable submarket proximity. Our county-deed-anchored comp pool for the same submarket and timeframe typically yields 11-16 transactions — a meaningfully larger sample that tightens the confidence interval on the cap rate estimate and reduces the reliance on metro-wide or national backstop comps.
The International Capital Problem and Price Interpretation
A second and analytically distinct Miami data challenge involves the role of international capital in distorting cap rate signals. Miami-Dade is one of the few US markets where a significant volume of commercial transactions involve buyers who are optimizing for capital preservation and US asset exposure rather than income yield. These buyers may transact at cap rates that are 30-100bps below what a domestic institutional buyer would require on the same asset.
For a comp pool, this creates a systematic downward bias in the cap rate distribution if international-capital transactions are included without adjustment. A transaction at a 4.2% cap rate where the buyer is a South American family office converting hard currency to US real estate is not an appropriate comp for a domestic REIT calculating its required return on an institutional acquisition.
We address this through a buyer-type classification applied to the county deed record. Where the grantee is a foreign entity (identifiable by country of incorporation in the deed filing or by state-of-formation in the entity registration record), we flag the transaction for review. Where the price implies a cap rate that is more than one standard deviation below the distribution of identifiable domestic institutional transactions in the submarket, the transaction is down-weighted in the comp pool or excluded from the Tier 1 cap rate derivation.
CMBS Coverage in Miami: Partial but Valuable
Miami's multifamily and office assets have CMBS coverage that is meaningful but not comprehensive. CMBS-encumbered properties represent roughly 28-35% of institutional-grade commercial assets in Miami-Dade, lower than in markets like Phoenix (where CMBS penetration in multifamily is higher) but still a significant share. For these assets, monthly servicer remittance data provides actual occupancy, DSCR, and NOI — materially improving the quality of the NOI estimate relative to market-average benchmarks.
Assets without CMBS exposure — the majority of Miami multifamily in the sub-$15M segment — must rely on submarket rent and vacancy benchmarks from Census, NCREIF, and HUD data. These benchmarks are accurate at the metro level but imprecise at the submarket level in a market as internally diverse as Miami-Dade, where rent levels in Brickell can be 2.5x those in Miami Gardens despite both being within the same county.
We solve this with a submarket indexing layer that divides Miami-Dade into 18 distinct submarkets — Brickell/Downtown, Edgewater/Wynwood, Coconut Grove, Coral Gables, Hialeah, Homestead, etc. — and maintains separate rent and vacancy benchmarks for each. This adds infrastructure cost but meaningfully improves the precision of NOI estimates for properties where CMBS data is unavailable.
What This Means for Underwriters
For acquisition analysts running Miami commercial underwriting, several practical implications follow:
- Treat broker-reported comp pools as a starting point, not a complete picture. For assets in the sub-$25M multifamily and mixed-use segment, the gap between broker-reported and total transaction volume is large enough to materially affect comp pool depth and confidence interval width.
- Scrutinize cap rate comps for buyer type. In Miami, the buyer universe includes a higher share of non-yield-optimizing capital than most US markets. Comps from foreign-entity buyers should be reviewed for whether they represent market yield expectations or capital preservation priorities.
- Use CMBS servicer data as an anchor where available, but recognize that CMBS coverage is partial in the Miami market — particularly in the sub-$15M segment where conventional bank financing dominates.
- Expect wider confidence intervals in Miami submarkets than in more transaction-dense markets. The appropriate response to a wide confidence interval is not to ignore it — it is to recognize that the market is genuinely thin for that asset type and location, and to price accordingly.
Miami commercial real estate is one of the more analytically demanding markets in the US precisely because its growth has outpaced the data infrastructure that tracks it. Building a defensible valuation in this market requires stitching together public record data that most national models do not ingest. That stitching effort is exactly what Valuevynt was built to do.
