Household Formation Just Hit a 10-Year Low. Here’s Why That’s a Demographic Tailwind for Self-Storage.

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The most important number in the M&M report this month is not supply, not rent, not vacancy.

It is 0.4%.

That is the rate at which US households are forming right now. Half of the prior decade’s average of 0.8%. The lowest reading in about ten years.

Here is the deal. Fewer households forming means fewer people moving. Fewer people moving means fewer storage units rented. On its face, that looks like a headwind for the sector.

But that is not the full picture. The full picture is what happens next.

What a 0.4% formation rate actually means

The M&M report published this number inside its U.S. Self-Storage Outlook for the second half of 2026. It is not buried — it is tabulated alongside supply completions and vacancy forecasts as one of the structural conditions shaping the market.

The 0.4% reading means that out of roughly 265 million working-age adults in the country, the net new household count grew by about 1.1 million over the year. That is about half the pace of the 2010s.

Why did it slow? Housing costs are the dominant reason. Mortgage rates, rents, and purchase prices all ran high enough that young adults delayed leaving shared living situations. The household formation rate in the 2010s was boosted by the post-GFC recovery and the millennial generation entering its prime household-formation years. Those same people are still in their prime formation years — they just have not formed yet.

That distinction matters. The people who did not form households in 2024, 2025, and 2026 are not disappearing. They are waiting.

Why this matters for storage demand

Storage demand is tied to household formation by a straightforward mechanism. Moving generates storage. A person who rents an apartment or buys a house almost always has more stuff than the new place accommodates immediately. The gap between what they own and what fits fills a storage unit.

A person who does not move does not generate that need.

But when the person who delayed moving finally does move — a year from now, three years from now, five years from now — they generate the same storage need. Compressed into a shorter period. The demand does not disappear. It concentrates.

We see this pattern in the tenure data Oakside and Placer.ai tracked: the average tenant stay lengthened from 9 months to 18 months because housing turnover stalled. The people who are already in units are staying longer. The people who have not formed yet will form eventually. Both forces point the same direction for an owner who holds through the window.

The demographic weight behind it

The 25-to-44 age cohort — the primary household-formation and moving demographic — is the largest it has ever been in absolute terms. Roughly 87 million people. Larger than the baby boomer generation at the same stage.

That cohort is currently forming households at half the historical rate for its size. That is not a sign the cohort is smaller. It is a sign the output is delayed.

The math is straightforward. If 87 million people in their prime formation years are forming at half the rate of the prior cohort, the catch-up formation — the households that would have formed in a normal rate environment but have not yet — sits at roughly 3 to 4 million delayed formations over the 2023-2026 period.

Each of those delayed formations, when it eventually happens, generates a storage need. Even at conservative capture rates, that is tens of millions of square feet of demand that has not yet expressed.

Run the numbers.Pull your target market’s age demographics from the census. Count how many people are in the 25-to-44 cohort. Compare that to the current formation rate in that market. If the cohort is large and the rate is below the historical average, the compressed demand is arithmetic, not hope. The deal either works at the current numbers or it does not. Run the numbers. Then run them again.