Underwriting Multifamily in 2026's Two-Speed Market

Published May 29, 2026

For three years, multifamily underwriting was a fight against new supply. The largest delivery wave since the 1980s pushed roughly 1.8 million units into the market over three years (per CoStar), pressured rents in fast-growing metros, and forced operators to compete on concessions. Heading into 2026, the story is shifting — but not everywhere at once. New apartment starts have fallen sharply from their peak, and national asking-rent growth has just nudged back into positive territory at around 0.4% year-over-year (per CoStar's March 2026 report; RealPage's effective-rent measure was modestly negative on a different methodology), signaling the cycle may have turned. The catch: vacancy is still running near 8.6% nationally (per CoStar) — among the highest levels since the post-financial-crisis recovery — and that recovery is not arriving evenly.

The problem for underwriters is the word "evenly." The market has not recovered as one. It has split into two speeds, and a single set of national assumptions can now get a model wrong in both directions. Underwrite a coastal deal with Sun Belt pessimism and it loses to a more aggressive bidder. Underwrite a Sun Belt deal with national-average optimism and the basis overpays into a still-correcting market.

This post breaks down how to set rent-growth, occupancy, and exit-cap assumptions by metro type in 2026, and why underwriting to normalized conditions — rather than trough or peak — is a defensible posture right now.

Why the Market Split — and Why It Matters to Your Model

The bifurcation comes down to where supply landed. High-growth Sun Belt and Mountain metros absorbed the bulk of new deliveries, and the overhang is still being leased. Supply-constrained coastal and Midwest markets added very little new stock, so their rents kept climbing even through the downturn.

The numbers tell the story plainly. Since the start of 2023, the steepest cumulative rent declines have been in Austin and Phoenix, while New York City, Chicago, and Kansas City have led on the upside — a spread of roughly 20-plus points top to bottom (approximate cumulative figures derived from CoStar metro data; treat as directional). More recently, San Francisco has posted some of the strongest rent growth of any major metro, with asking rent up roughly 6.3% year-over-year for the 12 months ending in March 2026 and San Jose close behind near 3.6% (per CoStar) — both tied to the AI investment wave. Meanwhile, Austin may be approaching a bottom: after roughly 10 consecutive quarters of rent declines (per Colliers), sharply falling new supply could set the stage for stabilization. These are not minor regional wobbles — a swing of that magnitude over three years dominates the rent line in any hold-period projection.

For an underwriter, this means the first decision isn't the rent-growth number. It's the market bucket the deal falls into. Get that wrong and every downstream assumption inherits the error.

Bucket 1: High-Supply Metros Still Working Through the Overhang

Orlando, Austin, Miami, Nashville, and Phoenix are still adding meaningful new stock through 2026 and 2027 even as starts fall. Occupancy in much of the Sun Belt has been sitting in the low-to-mid 90s, and operators are leaning on concessions to fill new lease-ups.

How these markets are commonly approached in 2026:

• Near-term rent growth at or near zero. Many high-supply metros are not expected to reach meaningful positive asking-rent growth until late 2026. A flat-to-slightly-negative effective rent for the first 12 months is more defensible than a V-shaped snap-back — and where a market like Austin is showing early signs of bottoming, that reads as recovery toward zero, not a green light for aggressive growth.
• Concessions as a real line item. A month or two of free rent on new leases meaningfully widens the gap between asking and effective rent. A model that only tracks asking rent overstates year-one revenue.
• Conservative exit caps. With near-term operational stress, cap rates in these markets are broadly expected to stay roughly stable rather than compress quickly. Underwriting aggressive exit-cap compression to manufacture a return is a bet that needs evidence.

Bucket 2: Supply-Constrained Coastal and Midwest Metros

Boston, Washington D.C., New York, Chicago, Indianapolis, Kansas City, Columbus, and Detroit share a common trait: limited new construction and healthy absorption. Forecasts point to modest but positive rent growth in these markets — Yardi Matrix has projected Midwest metros around 3% to 4.5% and supply-constrained coastal markets around 2% to 3% for 2026, and as of March 2026 the Midwest was already posting roughly 1.9% year-over-year with New York near 4.8% (per CoStar).

How these markets are commonly approached:

• Positive but disciplined rent growth. Low-single-digit growth is supportable here in a way it currently is not in the Sun Belt. But "supply-constrained" is not "uncapped" — year-one growth grounded in submarket comps holds up better than the metro headline.
• Capital is competing for these assets. Investors are gravitating toward metros with regulatory or geographic limits on new building and stable employment. That competition compresses going-in yields, so the acquisition basis has less margin for error.
• Watch building class. The new-supply glut landed hardest on the top of the market: per CoStar, mid-tier (3-Star) product led rent growth in 2025 (around +0.3%) while 4- and 5-Star assets fell (around −0.4%) under concession pressure, with CoStar expecting that to invert as luxury lease-up clears in 2026. Class can matter as much as metro. (See value-add multifamily for how class interacts with the business plan.)

The One Assumption That Quietly Destroys Returns: Exit Cap Rate

In a bifurcated market, the exit cap rate is where optimism does the most damage. The temptation is to assume compression because "rates are coming down." But cap rates are broadly expected to hold roughly stable in 2026 with only incremental compression in later years — and that's a base case, not a guarantee.

A disciplined approach:

1. Treat the going-in cap rate as the floor for the exit assumption. Expanding the exit cap relative to entry is conservative; compressing it is a bet that needs real evidence behind it.
2. Run a sensitivity table. A 50-basis-point swing in exit cap can move IRR by several hundred basis points. If the deal only works at a compressed exit, it doesn't really work.
3. Underwrite to normalized NOI, not trough or peak. The institutional consensus leans toward stabilized conditions and conservative leverage rather than today's depressed numbers or yesterday's peak rents.

What Holds the Demand Side Up

None of this means demand is weak. The structural housing shortage — estimated at roughly 4 million units by the National Association of Realtors and as high as 4.7 million by Zillow and the U.S. Chamber of Commerce — a steep buy-versus-rent premium, falling move-out-to-purchase rates, and Gen Z entering its prime renting years all support multifamily demand through the forecast period. Renewals are running at historically high levels, which cushions occupancy even when new-lease pricing is soft.

The one genuine wildcard is immigration policy, which sits upstream of household formation. A loosening could accelerate demand recovery; sustained restrictions could extend the soft patch. Policy isn't something a model can predict, but it can be stress-tested: run a downside case with slower household formation and see whether the deal survives.

The Underwriting Takeaway for 2026

The supply cliff is real, and it favors patient, disciplined buyers. But it does not lift all markets at the same time, and it does not reward national-average assumptions.

Three rules for the year:

• Bucket first, then assume. Identify whether a deal sits in a high-supply or supply-constrained market before touching the rent line.
• Separate asking from effective rent. Concessions are the difference between a model that pencils and one that's fiction.
• Earn the exit cap. Stable-to-expanding is the responsible base case; compression is a thesis that has to be defended.

The sponsors who come out ahead in this cycle are unlikely to be the ones with the most optimistic spreadsheets. They're more likely to be the ones whose models still hold up when the rent-growth line is flat and the exit cap doesn't move.

UWmatic is an AI-powered underwriting platform built for multifamily and mobile home park investors. Bucket a deal, separate asking from effective rent, and run exit-cap sensitivities on a real rent roll in minutes — then export a lender- and LP-ready package. Try the free underwriting calculator →

This analysis reflects current market interpretations as of the publication date and may evolve as new data becomes available. Figures cited are drawn from public sources including CoStar and Yardi Matrix multifamily data, Colliers and CBRE market commentary, National Association of Realtors and Zillow / U.S. Chamber of Commerce housing-supply estimates, and Census household-formation data, and are subject to revision. Nothing in this post is investment advice; readers should conduct their own diligence and consult qualified professionals before making investment decisions.