US Flash PMI — August 2026: Fastest Growth Since April 2022

August's flash reading extends a two-month acceleration and puts the composite at its highest in 52 months. The mix matters: services drove the gain while manufacturing cooled to a five-month low, a rotation S&P Global describes as momentum shifting between the second and third quarters.^[1][2]

The caveats sit on the supply side. Delivery delays stretched to near four-year extremes — attributed to shipping disruption, tariffs and thin supplier inventories — and the report warns price pressures, though fading, remain vulnerable to renewed energy-cost increases.^[1]

The most common way to misread a PMI headline is to treat it as a growth rate. It is not one. The PMI is a diffusion index, and the published methodology gives the formula plainly: «INDEX VALUE = (% 'up') + (0.5 * (% 'the same')) + (0.0 * (% reporting 'down'))». A reading of 56 therefore says that more firms reported improvement than deterioration — not that output rose 6%.^[4]

The clearest illustration comes from the other US survey. When ISM reported a manufacturing PMI of 54.6% for August 2026, it also stated what that implies for the economy: the reading «corresponds to a 2.4-percent increase in real gross domestic product (GDP) on an annualized basis». So 54.6 maps to roughly 2.4% growth — the index level and the growth rate are different scales entirely.^[5]

A second consequence catches readers out when the index falls. The methodology gives its own example: a move from 55.0 in January to 52.5 in February does not mean output shrank. Both months are above 50, so «the volume of output expanded in both January and February, but the rate of increase was slower in February». Direction is set by the 50 line; the distance from 50 indicates how fast, not how much.^[4]

Searching for 'US PMI' returns two different indices — S&P Global's and ISM's — and they can point different ways in the same month. They are built differently: S&P Global surveys a larger panel and weights responses by company size and sector, while ISM's panel is self-weighting, and the two use different component weights for their headline figures.^[4][5]

The levels also differ systematically. S&P Global's own comparison notes that the ISM business activity index has averaged well above the equivalent S&P Global index since 2010, so the same underlying economy produces higher ISM numbers. Comparing an ISM reading with an S&P Global reading as though they were the same scale will overstate or understate the change. (That comparison is published by S&P Global itself, so it is not a neutral source on which survey is better.)^[4]

For August 2026 the two agreed on manufacturing: ISM fell to 54.6% from 55.6%, and S&P Global's manufacturing reading also eased. The divergence in the headlines came from services, where S&P Global's flash showed a sharp acceleration.^[1][5]

The flash release is not a preliminary guess calculated differently — it is the same calculation on an earlier sample. The methodology describes it as an early cut comprising 80–85% of the final sample, with the remainder arriving before the final release. Revisions are usually small but not trivial: July 2026's services reading was revised from a flash 53.6 to a final 54.6.^[1][4]

As of this update the final August figures had not yet been published, so any August number circulating as 'final' should be checked against the release date. The next flash release covering September is scheduled for late September, and ISM stated its next manufacturing report — covering September 2026 — will be released at 10:00 a.m. ET on October 1, 2026.^[4][5]