The reading

Green Street reported on September 4, 2026 that its Commercial Property Price Index rose 0.8 percent during August, leaving the all-property index 5.0 percent higher than twelve months earlier.

The month-by-month path through 2026 has been uneven rather than steadily rising. The index was unchanged in June with a 4.1 percent twelve-month gain; rose 1.0 percent in July to a 5.2 percent annual gain; and rose 1.6 percent in May, also against a 4.1 percent annual figure. August's 0.8 percent is therefore a deceleration from July, and the annual rate ticked down with it.

Why this index moves before the transaction data

The CPPI is built from valuations and cap rates on REIT-owned assets rather than from recorded sales. That construction has one large advantage and one large limitation.

The advantage is timeliness. Transaction-based indices only register a price when a deal closes, which is typically several months after the price was agreed, and they register nothing at all when volume dries up. A valuation-based index keeps reporting through a frozen market.

The limitation is that it is an estimate of what assets would fetch, not a record of what they did fetch. In periods when bid and ask are far apart, the index reflects the modelled midpoint rather than the absence of clearing. Readers should treat it as the fastest available signal, not the most definitive one.

The rate constraint, in the firm's own words

Peter Rothemund, the firm's co-head of strategic research, attributed the headwind to rising Treasury yields, saying they were likely to cause buyers to rethink what they are willing to pay.

The mechanism is direct. Commercial property is priced off a spread to the risk-free rate. When the ten-year Treasury yield rises and property cap rates do not, the compensation for illiquidity, management and tenant credit risk narrows. Buyers respond either by bidding less or by not bidding.

Analysis: an index up 5.0 percent over twelve months while the funding benchmark rises is a market where operating income growth is doing the work that cap-rate compression used to do. That is a healthier composition of return than the alternative, but a slower one, and it depends on tenant demand holding.

Sector dispersion under the headline

Green Street's sector breakdown, published alongside the August reading, shows industrial as the strongest major property type: values there rose 0.6 percent in August and 7 percent over twelve months, leaving industrial just 8 percent below its 2022 peak. The all-property index, by contrast, remains 13 percent below its 2022 peak even after the twelve-month gain of 5.0 percent.

That gap matters for how the headline should be read. An all-property index recovering more slowly than its strongest sector means other sectors — office and, on other measures, apartments — are recovering more slowly still or have kept falling. The 0.8 percent August move is a blend, not a description of any one property type.

A competing index shows a starker picture

MSCI's RCA CPPI, a transaction-based index built from closed sales rather than REIT valuations, put the US all-property annual gain at just 0.2 percent in July — its slowest since January 2025 — with apartment prices down 4.1 percent over the year and sitting 22 percent below their July 2022 peak, even as central business district office prices rose 9.9 percent.

The divergence between Green Street's 5.0 percent annual gain and RCA's 0.2 percent is consistent with the two indices' different construction rather than a contradiction: one is a valuation model built on REIT-owned, generally higher-quality assets, the other a record of completed transactions across a broader universe including apartments, which RCA shows falling sharply. Readers who cite either figure alone risk describing only part of the market.