Marcus & Millichap forecasts U.S. self-storage vacancy falling to 10% by year-end 2026, a 20 basis-point year-over-year decline, as 2026 deliveries slow to 2.2% of inventory in the brokerage's September 2026 outlook. First-half completions totaled 27.8 million square feet, the lowest January-June volume since 2014.
The report is the clearest institutional framing yet for a year operators have felt in the field: fewer keys turning, softer advertised rents, and more deals closing at the sub-$10 million tier. It aligns with Yardi Matrix retention data and Colliers' progress-not-recovery NOI call, but adds transaction and capital-markets math brokers see before it hits earnings calls.
Why Is Vacancy Expected to Improve Without a Demand Boom?
Marcus & Millichap does not describe 2026 as a demand rebound. Nationwide vacancy stayed elevated through June, but the brokerage expects fewer near-term completions to support occupancy in the second half.
The forecasted 10% year-end vacancy rate reflects stronger tenant retention and lower move-out activity rather than a meaningful increase in new customers. That matches REIT commentary this summer: occupancy ticks up while move-in volume keeps sliding.
Stabilized rents tell a split story. Average asking rents remain about 11% below the 2022 peak, yet stabilized in-place rents recovered to within one-half percent of recent highs. Existing tenants are holding; new prospects still shop discounts.
| Metric | Marcus & Millichap September 2026 outlook |
|---|---|
| Year-end 2026 vacancy forecast | 10% (-20 bps YoY) |
| 2026 supply growth | 2.2% of inventory |
| H1 2026 completions | 27.8M SF |
| Full-year completion forecast | ~53M SF |
| 2026 asking rent change | -0.8% to ~$1.18/SF |
Where Is Construction Still Concentrated?
Development slowed, but it did not stop. Atlanta, Dallas-Fort Worth, Houston, Orlando, and Tampa-St. Petersburg each added more than 1 million square feet in the first half of 2026.
The Western U.S. posted its lowest first-half development volume since 2017. Midwest completions hit the lowest first-half level since 2012. The second-half pipeline remains Sun Belt heavy: Phoenix, Houston, Southeast Florida, Tampa, Orlando, and DFW lead the queue.
Operators in those metros still compete on price. Marcus & Millichap notes Sun Belt street rates softened more than other regions as new product lease-up. Marcus & Millichap's August deal roundup showed buyers still chasing Texas and Florida assets, but underwriting now assumes longer lease-up, not instant stabilization.
How Did Investment Activity Recover in the First Half of 2026?
Transaction velocity is the bullish line in the report. Sales activity rose nearly 20% year over year through June 2026. Total deal volume rose nearly 50%. Both metrics remain below the 2022 peak, but the 2024 trough is fading.
Size skew matters. Deals above $20 million trail 2022 by 65%. Deals between $1 million and $10 million account for most volume over the past year. The Mountain region led with a 75% year-over-year increase in transactions and was the only region to exceed 2022 activity. The South remained largest by count and dollars.
That pattern shows up in September closings: Reframe's $10.55 million Mount Pleasant buy and Marcus & Millichap's Wisconsin portfolio trade sit exactly in the active band, while mega-cap REIT M&A stays episodic.
What Are REITs Doing While Same-Store Rents Flatline?
Public operators are growing managed footprints faster than owned square footage. Managed facilities across Extra Space, Public Storage, and CubeSmart grew at a 14.7% annualized rate from 2023 through 2025, reaching 3,224 stores by June 2026.
Third-party management is a capital-light way to scale brand and fee income when balance-sheet acquisitions compete with elevated watchlist exposure on 2021-2024 CMBS. Marcus & Millichap frames it as competitive pressure on independents; for REITs it is also a hedge when owned same-store revenue wobbles.
Public Storage's ChatGPT search pilot and platform M&A show the same instinct: control the customer front door even when you do not own every door on the block.
How Tight Are Capital Markets for Storage Deals?
Average sector cap rates registered 6.59% in 2026 while the 10-year Treasury hit 4.76% in late August. The spread compressed because yields rose, not because sellers suddenly accepted lower returns.
Lending mix shifted. Banks and credit unions represented roughly 70% of self-storage lending volume in 2023 but closer to half in 2026, with debt funds, government programs, and CMBS picking up share. Securitized delinquency stood at 0.05% in July, but nearly 30% of outstanding balances sat on servicer watchlists, concentrated in 2021-2024 originations.
First Citizens' $157 million Blue Doors Fund IV close is the other side of that coin: specialized lenders still raise dedicated storage equity when regional banks pull back.
The Numbers Worth Writing Down
- Report: Marcus & Millichap U.S. Self-Storage Outlook, published September 2026
- Year-end 2026 vacancy: 10% (forecast, -20 bps YoY)
- 2026 supply growth: 2.2% of inventory (smallest since 2016)
- H1 2026 completions: 27.8 million SF (lowest H1 since 2014)
- 2026 asking rent change: -0.8% to ~$1.18/SF
- H1 2026 transaction volume: +~50% YoY; sales count +~20% YoY
- Deals >$20M vs 2022: -65%
- Average cap rate: 6.59%; 10-year Treasury 4.76% (late August 2026)
- REIT managed store count (top 3): 3,224 as of June 2026
Supply Discipline Is the Forecast
Marcus & Millichap's September 2026 outlook is not a victory lap. It is a supply story with a cautious demand footnote. Vacancy improves because builders delivered the smallest relative pipeline in a decade, and because tenants stopped leaving at 2023 pace.
Operators who need street-rate growth still wait on household mobility. Household formation grew only 0.4% year over year through June 2026, roughly half the prior decade's average, with elevated shares of young adults living in parental homes.
Buyers should read the transaction rebound as liquidity returning to the middle market, not as a return to 2022 pricing. Sellers with 2016-2019 vintage assets in supply-light metros still have leverage. Sellers in Sun Belt lease-up wars do not.
The full report lives on Marcus & Millichap's research site. The sector summary you need for Monday morning is simpler: 10% vacancy, 2.2% supply, and deals getting done without asking rents leading the way.
Sources
- U.S. Self-Storage Outlook 2026: Vacancy Improvement Emerges as Development Slows, Marcus & Millichap
- Self-storage sector begins to stabilize after years of overbuilding, Scotsman Guide
- Self-Storage Real Estate Acquisitions and Sales: September 2026, Inside Self-Storage