Amazon closed the 21 days to August 31 at 1,705 SEO visibility points, down 16.9%, its lowest reading since tracking began in November 2022. The drop landed inside a data window where Google ran a spam update from August 18 to 21 and served fewer PDF files in results for roughly two weeks, according to the latest Growth Intelligence Brief, built on the Search Signals Index (SSI) — a fixed panel of roughly 2,600 companies across 26 verticals, tracked week after week on SEO visibility and AI mentions, in the manner of an S&P 500 for organic search.

The index as a whole slipped 2.4% across 1,842 companies in the 21 days to August 31. Six trends carried the move, and three stand out for search professionals.

Amazon's record low, and where the ad money went

Amazon fell from 2,051 to 1,705 points. The same three-week window cost Amazon only 1.1% in 2023, 0.7% in 2024 and 9.5% in 2025 — this year's loss is nearly double the worst prior August. The slide compounds a longer decline from 3,560 points in November 2024 to 2,226 in January 2026, and it happened while the broader index slipped just 2.4%.

Advertising budgets moved in the same direction during the window. Back-to-school spending on TikTok rose 20 to 40% year over year across July and August, TikTok Shop sales grew 84% in the year to February, and Go Fish Digital's clients shifted money to TikTok after hitting "max spend on Amazon and Google," finding TikTok "right behind Amazon" in sales volume. Google search costs rose about 20% in August at the same time. In short: advertisers hit their ceiling on Amazon and Google and routed the overflow to TikTok Shop while Amazon's organic shelf shrank. Notably, TikTok itself sits at its lowest Google visibility since September 2025 — the platform winning retail budget is losing Google's shelf while it does.

Ecommerce as a vertical fell 7.9% across 290 companies, giving back its August gain, with Amazon carrying 346 of the vertical's 451 lost points. Home Depot fell 14.7% (315 to 268) after gaining 27.0% in the prior issue's window; Wayfair fell 26.5%, Best Buy 9.4% and Target 5.7%. Walmart, up 5.9%, was the only large retailer to gain.

The August 2026 spam update: one noisy week, quiet neighbors

Google confirmed the August 2026 spam update ran from August 18 to 21, inside calendar week 34 (August 17 to 23). Trackers logged more volatility after it ended, with no announcement explaining it — so treat the post-update churn as tool-signal observation, not a confirmed Google action.

The numbers from the index: week 34 moved 40 of 754 companies with a baseline above 3 by more than 20%, a 5.3% churn rate, half of week 31's 11.0%. The weeks on either side were quiet — 2 companies in week 33, none in week 35. This is consistent with a short, contained re-sorting rather than a sustained shakeout.

Two confirmed Google policy changes landed in the same period. Under a European Commission mandate, Google stopped enforcing site reputation abuse manual actions in the EEA from August 30; flagged sections there now get separated in ranking rather than suppressed. And Google now routes search clicks through google.com/goto redirects at what Nozzle's Derek Perkins logged as a near-100% rollout, after testing that began in July — a change aimed at scrapers. Practical consequence: any rank tracker has to follow the redirect to see the destination URL, so check your tracker's data continuity from late August before trusting its numbers.

Fewer PDFs, and the IRS paid for it

Google served fewer PDF files in results for two weeks during the window, and government domains that lean on PDF-heavy content absorbed the hit. The IRS lost 59.6% (from 69 to 28 points), the Small Business Administration lost 52.8%, and the Department of Education lost 30.8% in the 21 days to August 31. The other 40 federal domains in the index round-tripped — they ended the window roughly where they started. The pattern points to a SERP-level change in PDF surfacing rather than a domain-level penalty, though the brief attributes causality by timing, not by any Google statement.

Platform winners and losers

YouTube gained 8.7% (3,391 to 3,687), its first up-window after two down issues. Reddit fell 9.3% to its lowest level since April. TikTok fell 20.3% to its lowest since September 2025.

Images rose 13.9% in the 21 days to August 31 — the largest vertical gain in the index. The split inside the vertical is stark: paid stock libraries rose 23.8% together (Getty Images +24.4%, Shutterstock +22.9%) while the free libraries slipped 2.7%.

Wikipedia lost 5.6%, from 8,280 to 7,820 — the largest raw loss in the index at 460 points. References as a vertical fell 4.8%, the largest share loss in the index.

What to watch

The confirmed events to track next: whether Google's goto redirect rollout stabilizes tracker data continuity, how the EEA's new site-reputation-abuse treatment affects rankings for European domains, and whether the PDF reduction persists into September — the IRS, SBA and Education Department numbers will show quickly if it does. On the tool-signal side, watch whether Amazon extends its record-low slide or follows its seasonal pattern of partial recovery, and whether TikTok's visibility continues to diverge from its ad-revenue trajectory.