How AI Search Is Recommending PEO Services: Monthly Trends

Executive Summary

ADP TotalSource remains the benchmark's coverage leader in September 2026 at 37.4%, but its lead has narrowed substantially to 1.8 points over Justworks, which moved back into second place at 35.6%. This represents a meaningful reordering from August 2026, when ADP TotalSource led TriNet by 4.6 points and Justworks sat in third. The leader's two-month decline of 7.1 points from 44.5% in July is significant, while Justworks' overall 7.6 point drop from July masks a stabilizing August-to-September picture.

ADP TotalSource and Justworks were the category's two significant decliners over the July-to-September series. ADP TotalSource fell 7.1 points from 44.5% to 37.4%, alongside drops in top-three recommendation rate (down 8.7 points to 26.8%) and rank-one rate (down 11.6 points to 11.9%). Justworks declined 7.6 points from 43.2% to 35.6%, with the bulk of that movement occurring between July and August; it regained 0.2 points in September. No brand recorded a significant upward movement across the series, and no brand moved beyond normal variation in the single month of September.

The category's overall movement in September was quiet. Eight of ten brands were classified as stable on a month-to-month basis, and the two significant declines are baseline-to-current movements accumulated across the three-month series. TriNet showed the strongest supporting signal, with raw mention presence up 7.4 points to 67.4% and top-three recommendation rate up 5.5 points to 20.7%, even though its coverage change of down 1.6 points remained within normal variation.

Each monthly run begins with 756 prompt-surface observations (434 unique questions) in July 2026, 769 (527 unique questions) in August 2026, and 790 (526 unique questions) in September 2026 across the benchmark's defined AI/search surface universe. Of those, 756 mentioned a tracked brand or competitor in July, 768 in August, and 789 in September; 710 were relevant and 46 were irrelevant in July, 726 were relevant and 42 were irrelevant in August, and 755 were relevant and 34 were irrelevant in September. The public metrics use the 400 observations that survived both qualification stages in July, the 393 in August, and the 396 in September.

Key Findings

Benchmark Context

The report separates the raw collection universe from the qualified analysis set. Brand-level recommendation percentages are calculated within the qualified benchmark set.

Benchmark-Level Metrics

AI Recommendation Trend

Leadership Retained, Lead Compressed

ADP TotalSource has led the category in all three months, though its September lead of 1.8 points over second-place Justworks is the narrowest of the series, with TriNet (34.6%) and Insperity (31.8%) also inside a tightly clustered top tier. ADP TotalSource and Justworks were the only brands whose coverage moved beyond normal month-to-month variation, both declining across the July-to-September series; the compression at the top reflects the two leaders' pullback rather than any single brand's rise.

What Changed This Month

ADP TotalSource: Significant Decline Narrows the Lead

ADP TotalSource's valid recommendation coverage fell 7.1 points from 44.5% in July to 37.4% in September, a significant decline across the series. On a prior-month comparison, the brand fell 4.3 points from August's 41.7%, a change within normal month-to-month variation. The brand has now declined in two consecutive months.

The erosion runs deeper than overall coverage. Top-three recommendation rate fell 8.7 points to 26.8% (106 observations), and rank-one rate fell 11.6 points to 11.9% (47 observations). Raw mention presence declined 3.0 points to 70.5%. The valid recommendation count fell from 178 observations in July to 148 in September.

The distinction to notice: ADP TotalSource remains the most-present brand in the category, but its recommendation rate is falling faster than its presence. This is a placement problem more than a visibility problem; the brand appears in answers but is recommended less often and lower.

Highest-priority diagnostic: Which prompt categories drove the loss of top-three and rank-one recommendations, and which brands are capturing those slots?

Justworks: Two-Month Decline, But September Stabilized

Justworks' coverage fell 7.6 points from 43.2% in July to 35.6% in September, a significant decline across the series. Unlike ADP TotalSource, however, Justworks gained 0.2 points between August and September, indicating the decline occurred almost entirely in the earlier month. Its raw presence rate fell 4.8 points to 68.2%.

The brand's rank-one recommendation rate rose 5.6 points to 14.4% (57 observations). Its top-three rate held nearly steady at 24.5% (97 observations), down just 1.3 points. The valid recommendation count fell from 173 observations in July to 141 in September, but the average rank improved to 2.6 from 3.1 in July.

The distinction to notice: Justworks is being recommended less often overall but surfaces higher when it appears. This mirrors its August pattern; the September stabilization suggests the decline may have run its course, while ADP TotalSource's continued drop keeps the gap narrow.

Highest-priority diagnostic: Which surfaces or prompt types drove the rank-one gains, and can that placement strength translate back into broader coverage?

TriNet: Strong Supporting Signals Without a Coverage Breakthrough

TriNet's coverage fell a non-significant 1.6 points from 36.2% in July to 34.6% in September, leaving it in third place. The notable movement is in supporting metrics: raw mention presence rose 7.4 points to 67.4% and top-three recommendation rate rose 5.5 points to 20.7% (82 observations). Rank-one rate rose 0.8 points to 3.0% (12 observations).

The valid recommendation count fell from 145 observations in July to 137 in September, even as presence and top-three placement rose. This combination suggests the broader recommendation pool shrank while TriNet held its position within it. The brand is increasingly present and increasingly placed in the top three, yet overall coverage did not follow, a pattern worth investigating at the prompt level.

The distinction to notice: TriNet's movement is the inverse of ADP TotalSource's. Where the leader loses placement despite high presence, TriNet gains placement and presence without a coverage gain.

Highest-priority diagnostic: Which prompts give TriNet top-three placement, and why does that strength not translate into higher overall coverage?

Buyer-Intent Interpretation

In September 2026, all 396 qualified observations fell into the Brand Recommendation cluster. The benchmark did not qualify observations for Pricing and Value or Multi-Brand Comparison in any month of the series, so the public metrics cannot yet describe how AI systems discuss price, value, or direct head-to-head comparisons among PEO providers. The current benchmark evidence is concentrated entirely on which brands AI systems recommend during the discovery and consideration phase.

Brand Opportunity Summary

The benchmark identifies where attention is warranted; a company-level analysis is needed to explain why.

Evidence Behind the Benchmark

The aggregate metrics are built from prompt-level observations covering the query, surface, recommendation outcome, rank, sentiment, and citations where exposed. Company-level analysis can go deeper into prompt, competitor, surface, and evidence patterns. Source presence is not automatically treated as proof of causation.

About This Benchmark

This report is part of the LLM Authority Index AI Market Discovery research program.

• AI Industry Market Discovery Methodology
• AI Industry Market Discovery Metrics
• AI Industry Market Discovery Standards

Report-Specific Interpretation Notes

• Small-count movements: Brands with single-digit coverage (CoAdvantage, Engage PEO, G&A Partners, Vensure Employer Solutions) move on very few observations; a change of a few percentage points can reflect a handful of recommendations. Absolute counts are named alongside percentages where relevant.
• Qualified denominator vs raw collection: Brand-level percentages are calculated within the 400 (July), 393 (August), and 396 (September) qualified observations, not the larger raw prompt collection. This keeps the public metrics consistent across the surfaces that qualify.
• Directional analysis: Month-over-month movement identifies changes worth investigating, but does not by itself establish the cause of those changes. The significant baseline-to-current movements signal where to look, not why the change occurred.

Next Step

The Public Benchmark Shows Where a Brand Is Winning or Losing. A Company-Level Audit Shows Why.

The aggregate percentage masks the questions that matter: which high-intent prompts are won, which competitor takes the recommendation when a brand loses, what attributes AI systems associate with each provider, and which external sources shape those answers. ADP TotalSource's narrowing lead and Justworks' rank-one strength are visible in the aggregate; the prompts behind those movements are not.

A company-specific AI visibility audit maps those prompt, surface, competitor, ranking, sentiment, and evidence-source patterns into a prioritized visibility strategy. The benchmark shows the scoreboard; the audit explains the game.

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