Green Street expects U.S. self-storage sector net operating income to be flat year over year in 2026 before growth resumes in 2027, per a September 9, 2026 Colliers Quick Hits report. Occupancy near 93%, improving move-in rents, and supply growth near 2% through 2030 support stabilization. Colliers' headline is blunt: progress, not recovery.
The report lands one week after Yardi Matrix data showed Q2 2026 REIT revenue growth up 10 basis points as trailing 12-month deliveries fell to 2.4% of inventory. The two sources tell the same story from different angles: fundamentals are firming, but advertised rents still fell 1.6% year over year nationally through July 2026.
What Does Green Street's Upgraded 2026 Outlook Actually Say?
After several years of post-pandemic oversupply pressure, self-storage fundamentals are stabilizing. Colliers, citing Green Street Advisors, frames the sector as past the worst but not yet in expansion mode.
Demand conditions are improving yet remain below historical norms. Home sales near multi-decade lows limit a key driver of customer turnover. Occupancy has held around 93%. Move-in rents are gradually improving. Green Street's revised forecast calls for flat year-over-year sector NOI in 2026, with growth resuming in 2027.
Improving operating conditions point to continued stabilization across the self-storage sector.
- Steig Seaward, Colliers
That language matters for operators who read REIT guidance raises as a demand rebound signal. Public Storage raised full-year guidance after Q2 2026. Extra Space posted 3.5% same-store NOI growth by cutting expenses. The aggregate picture is stabilization driven by fewer move-outs and slowing supply, not a surge in new move-ins.
Why Is Supply Still the Sector's Strongest Support?
Colliers identifies supply constraint as the medium-term bull case. Elevated construction costs, expensive land, and underwriting uncertainty keep annual supply growth modest at roughly 2% through 2030.
That projection aligns with Yardi Matrix's August 2026 pipeline data, which showed national completions expected to fall 19% from 2025 levels with reductions continuing through 2028. The under-construction pipeline contracted to 2.1% of total stock in July 2026, amounting to 44.1 million net rentable square feet nationwide.
The combination of muted deliveries and resilient occupancy should gradually restore pricing power as markets absorb recent additions. Phoenix still leads top-30 metros in under-construction share at 6.6%, but even that market saw month-over-month pipeline contraction through July.
For developers, the message is clear: the 2021-2023 delivery wave is digesting. The next wave will be smaller, slower, and more selective.
What Do 5.4% Cap Rates Signal for Buyers?
Investor sentiment is improving alongside earnings expectations. Colliers notes valuations have moved up with fundamentals. Average cap rates near 5.4% mean expected returns trail other property sectors.
That is the tension in September 2026 capital markets: operating metrics are stabilizing, but pricing already reflects much of the recovery. Further upside requires fundamentals to outperform current expectations, not merely meet them.
| Metric | Colliers / Green Street Read (Sept. 2026) |
|---|---|
| 2026 NOI trajectory | Flat year over year |
| 2027 NOI trajectory | Return to growth |
| Occupancy | ~93% |
| Supply growth (through 2030) | ~2% annually |
| Average cap rate | ~5.4% |
| Relative return profile | Trails other property types |
Colliers' Tom de Jong has separately documented bridge lender handbacks as maturing debt meets tighter underwriting. The cap rate compression and bridge stress coexist: stabilized assets price well; transitional deals face higher scrutiny.
How Does This Compare to the Acquisition Market?
Stabilization does not freeze deal flow. Inland and Devon closed an 859-unit Joliet, Illinois, acquisition on September 10, 2026. Andover Properties bought an 800-unit Massachusetts facility the same day.
Buyers with operating platforms still compete for young Class A assets and value-add Northeast trades. Green Street's flat NOI forecast is a sector-level aggregate, not a prohibition on individual deals where rebranding, revenue management, or below-replacement-cost basis creates alpha.
The distinction: portfolio buyers pay for stabilization. Value-add buyers pay for operational lift. At 5.4% average cap rates, the margin for underwriting error is thinner than in 2023.
What Should Operators Do With a Progress-Not-Recovery Forecast?
Treat occupancy stability as the win. Flat NOI in 2026 is not failure when the prior three years featured aggressive supply additions and falling street rates. Holding 93% occupancy while supply growth decelerates is the setup for 2027 pricing power.
Do not confuse REIT guidance with demand surges. Expense cuts and move-out reduction drive NOI as much as rate growth in the current environment. Operators should track move-in volume separately from in-place rent growth.
Underwrite supply at 2%, not 4%. Green Street's through-2030 supply projection supports development discipline. Markets that still show 5%+ under-construction pipelines require local competitive analysis, not national averages.
Watch cap rate compression as a ceiling. If you are selling into institutional bids near 5.4%, you are selling into a market that already prices stabilization. If you are buying, you need a clear operational thesis, not a sector beta bet.
The Numbers Worth Writing Down
- Report date: September 9, 2026
- Source: Colliers Quick Hits, citing Green Street Advisors
- 2026 NOI forecast: Flat year over year
- 2027 NOI forecast: Growth resumes
- Occupancy: ~93%
- Supply growth (through 2030): ~2% annually
- Average cap rate: ~5.4%
- Demand driver constraint: Home sales near multi-decade lows
- Yardi Matrix July 2026 street rates: -1.6% year over year nationally
- Q2 2026 supply growth: 2.4% of inventory (trailing 12 months)
Stabilization Is the Base Case
Green Street's upgraded outlook is not a victory lap. It is a revised base case: flat NOI in 2026, growth in 2027, supply constrained, occupancy resilient, cap rates compressed.
Operators who survived the post-pandemic delivery wave get a breathing year. Operators who need double-digit same-store revenue growth to justify their basis do not. Progress, not recovery, is the honest read for September 2026.
Sources
- Quick Hits: Progress, Not Recovery: Self-Storage Finds Its Footing, Colliers, September 9, 2026
- Self-Storage Sector Stabilizes Q2 2026, Your CAIO
- Yardi Matrix Supply Forecast Q2 2026, Your CAIO
- Colliers Tom de Jong Bridge Loan Handbacks, Your CAIO
- Inland Devon Joliet Acquisition, Your CAIO