Sunbelt multifamily has been one of the most-discussed cap rate stories of the past two years. Inbound migration, constrained for-sale inventory, and aggressive institutional capital chasing yield in secondary and tertiary markets created a compression cycle that ran from late 2022 through mid-2024 before macroeconomic pressure began testing its limits. As of early 2025, the picture is more nuanced than the headline numbers suggest.
This piece looks at the specific comp data underlying Sunbelt multifamily cap rate movement — what markets have compressed the most, what signals in the rent roll and CMBS data explain it, and where the uncertainty widest for underwriters entering the market today.
The Compression Baseline: What the Transaction Data Shows
Across the major Sunbelt multifamily markets — Atlanta, Phoenix, Dallas-Fort Worth, Nashville, Charlotte, and Miami — cap rates on Class A garden-style and mid-rise assets compressed an average of 45 to 70 basis points over the 18-month window from Q2 2023 through Q3 2024. The compression was not uniform. Markets with the strongest net in-migration and the tightest rental vacancy compressed the most. Coastal Sunbelt markets — Miami in particular — ran slightly ahead of the inland markets through 2023 before a modest re-widening in early 2024 as new supply deliveries created temporary absorption pressure.
By Q4 2024, Sunbelt Class A multifamily cap rates in the strongest submarkets were trading in the 4.5% to 5.2% range, depending on asset vintage, location quality, and in-place rent level relative to market. The compression from 2022 peak cap rates of 5.0% to 5.8% in the same markets represents a meaningful value creation event for assets that went through lease-up during the period.
Cap rate compression in Sunbelt markets through 2024 was not a story about low interest rates alone. It was driven by sustained NOI growth — effective rents rising 8–14% annually in peak submarkets — which compressed going-in cap rates even as Treasury rates climbed.
The NOI Growth Contribution
The most important analytical point for underwriters looking at Sunbelt multifamily is that the cap rate compression story and the NOI growth story are linked but not identical. Cap rates compressed in part because buyers priced in forward NOI growth, not just because they accepted lower current yields.
Looking at the CMBS remittance data for multifamily loans originated in Phoenix and Atlanta between 2021 and 2023, in-place NOI on stabilized assets grew substantially relative to origination NOI in most cases. Servicer remittance reports show effective gross income increases of 9% to 16% on a per-unit basis for assets that went through a full rent roll mark-to-market during the period. That NOI growth, when capitalized at a stable cap rate, produced significant value appreciation independent of any multiple expansion.
The implication for current underwriting: an asset showing a 5.0% cap rate on current NOI at today's pricing may be pricing in some rent growth assumption. If that growth assumption is unrealistic given where we are in the Sunbelt supply cycle, the true risk-adjusted cap rate is wider than the in-place number suggests.
Supply Deliveries and the Absorption Pressure Window
Beginning in mid-2023 and running through 2025, Sunbelt markets absorbed a significant wave of new multifamily supply — units permitted and started during the 2021-2022 demand peak. The volume of deliveries varied significantly by market. Austin, where permit issuance was disproportionately high, saw effective rent growth stall and then reverse in 2024. Nashville and Charlotte experienced similar but less severe softness. Atlanta and Miami, where land constraints and construction cost escalation slowed permit volume more than demand, saw absorption pressure but not the sustained vacancy rise that hit Austin.
For underwriters, the absorption picture matters more than the absolute vacancy rate. A submarket with a 6.5% vacancy rate that has positive net absorption quarter-over-quarter has a fundamentally different risk profile than one with 6.5% vacancy that is flat or declining on absorption. The cap rate comp pool in a market with improving absorption will hold more tightly than one where comps are pricing in forward distress.
Atlanta
Atlanta Beltline-adjacent submarkets — Midtown, Old Fourth Ward, Inman Park — maintained some of the tightest multifamily vacancy in the metro through 2024, running 4.8% to 6.1% on Class A assets. Cap rates in these submarkets compressed to 4.7% to 5.0% on recent transactions. The broader metro vacancy, at around 7.8%, is meaningfully higher — Class B assets in outer-ring submarkets experienced more absorption pressure as new supply delivered in locations with longer commute profiles.
Phoenix
Phoenix multifamily saw supply-driven softness more broadly. The metro vacancy rate moved from approximately 5.9% in mid-2022 to 8.2% by Q3 2024 as deliveries outpaced demand in several submarkets. Cap rates in core Phoenix submarkets re-widened modestly from their 2023 compression lows, settling in the 5.0% to 5.4% range on Class A assets by late 2024. This is still notably below 2021 pricing levels but represents a meaningful shift from the sub-5.0% prints seen at the peak.
Miami
Miami multifamily represents a distinct market dynamic from most Sunbelt metros. Net in-migration into Miami-Dade remains structurally higher than in markets like Phoenix or Atlanta, driven by a combination of international capital, remote-work relocation, and a for-sale market that remains largely unaffordable for the renter cohort. Brickell, Edgewater, and Wynwood Class A multifamily cap rates compressed to 4.4% to 4.8% on 2024 transactions — among the tightest in the Sunbelt. Effective asking rents on newly stabilized product in Brickell reached $4.20 to $5.80 per square foot per month for high-rise units by late 2024, levels that would have been considered implausible as recently as 2019.
What the Comp Pool Tells Us About Confidence
One of the critical data points for any underwriter using automated valuation on Sunbelt multifamily is the depth and recency of the comp pool. In a market like Miami's Brickell submarket, where transaction volume for institutional-grade multifamily is relatively limited by the small geographic footprint, comp pools can thin quickly. A three-tier comp hierarchy — same-submarket, metro-wide, national backstop — is essential to produce defensible output when same-submarket comps are fewer than five transactions in the most recent 24 months.
In Phoenix, by contrast, transaction volume has been high enough that same-submarket comp pools are robust across multiple submarkets. The confidence interval on a Phoenix multifamily valuation is typically tighter — the interquartile spread of the comp pool's implied cap rates is narrower — than on a comparable Miami Brickell asset simply because there are more data points. This is not a reflection of relative market quality; it is a data availability fact that underwriters should calibrate their uncertainty around accordingly.
Rent Roll Dynamics: What to Look for in a Sunbelt Multifamily Underwrite
The rent roll analysis on a Sunbelt multifamily asset in 2025 requires attention to several dynamics that were less relevant in earlier cycles:
- In-place vs. market rent gap. Assets underwritten at the 2022-2023 peak with aggressive concessions to hit lease-up targets may have in-place rents that are still below current market — or they may have reached market but now face rollover risk as leases renew at potentially lower market rates in markets where new supply created pricing pressure.
- Loss-to-lease calculation. In markets where rents have softened from peak, the loss-to-lease line may be inverted — in-place rents above current asking. Underwriters need to apply a more conservative effective gross income assumption rather than projecting lease-up to current asking.
- Concession normalization. In supply-saturated submarkets, concessions of one to two months of free rent have become structurally embedded. These need to be treated as a component of effective rent calculation, not a temporary marketing expense.
- Operating expense escalation. Insurance premium inflation in Florida markets specifically has added $400 to $800 per unit annually to the expense load on coastal Florida multifamily, a meaningful drag on NOI for assets underwritten before 2022.
CMBS Signals as a Forward Indicator
One of the most useful data sources for tracking emerging distress in Sunbelt multifamily is CMBS servicer remittance data. For CMBS-encumbered multifamily assets — which represent a significant share of institutional multifamily in markets like Phoenix, Dallas, and Las Vegas — monthly servicer reports provide actual occupancy percentages, debt service coverage ratios, and delinquency status. This data is available via SEC EDGAR filings on CMBS trust reports and is updated monthly.
Tracking CMBS delinquency and special servicer transfer rates in a given submarket is a leading indicator for cap rate pressure. When DSCR deteriorates below 1.0x on a cluster of loans in a submarket, the market is in active distress and the comp pool will begin to include distressed sales, which are generally not appropriate comparables for stabilized assets. A well-constructed comp stacking methodology should identify and exclude distressed sales from the primary comp pool while flagging them as contextual information for the analyst.
What This Means for Underwriting in 2025
For analysts underwriting Sunbelt multifamily acquisitions in early 2025, the key framework adjustments from the 2021-2022 period are:
- Use current effective rents with market-realistic concession assumptions, not peak asking rents from 2023
- Apply supply delivery pipeline data to stress-test absorption assumptions — submarkets with 12 months of current vacancy absorption time and significant deliveries in the next 18 months face identifiable risk
- Treat the cap rate comp pool recency as a feature, not a formality — comps older than 24 months in a market that has experienced meaningful cap rate movement are not reliable anchors
- Use confidence intervals as a decision input — a valuation with a ±8% confidence range on a deal at the outer edge of your price capacity is a signal to seek more comparable data before committing to a letter of intent
The Sunbelt multifamily compression cycle is not over, but it has matured. The markets with the clearest forward fundamentals — persistent in-migration, constrained new supply, and positive absorption — remain attractive for institutional capital at the right price. The markets where the data is weakest — thin comp pools, elevated new supply pipelines, insurance cost headwinds — require proportionally more caution in the underwriting assumptions.
Valuevynt's comp-adjusted NOI model and confidence interval output are specifically designed for this environment: one where the point estimate matters less than understanding the full distribution of plausible values and the data quality underlying it.
