Across both Amazon and Walmart, the marketplaces still produced growth—but efficiency became fragile. The same spend decisions that worked in 2024 created very different outcomes in 2025 because costs rose, conversion got more sensitive, and the wrong mix/timing punished returns faster.

The headline: Amazon and Walmart are now on different maturity curves

If you’re still running a single “marketplace playbook,” the benchmark data says that’s a risk. (PS, download the full benchmark report here)

Amazon vs. Walmart: What the YoY benchmarks actually mean

Amazon: modest compression, driven by cost + softer conversion

  • ROAS: ↓ 3.9%
  • ACOS: ↑ 3.6%
  • CPC: ↑ 4.6%
  • CVR: 13.9% (↓ 4.4%)
  • AOV: ↑ ~5%

Amazon didn’t fall off. It tightened. A ~5% CPC increase looks manageable—until you pair it with a CVR decline. That’s what happened in 2025: incremental growth was still there, but it increasingly required precision(query control, bidding discipline, SKU prioritization). The saving grace was higher AOV, which helped cushion the blow.

2026 implication: On Amazon, the “unlock” isn’t more budget. It’s making the same budget work harder.

Walmart: scale grew faster than efficiency

  • ROAS: ↓ ~18%
  • ACOS: ↑ 20.2%
  • CPC: ↑ ~11%
  • CVR: 17% (↑ 1%)
  • AOV: ↓ ~9%

Walmart’s story is different: traffic still converted (CVR up slightly), but returns still fell hard. Why? Because the system absorbed more spend while order economics weakened. Walmart sellers effectively made a trade: pay higher CPCs to capture expanding demand, but take the hit when AOV didn’t keep up.

2026 implication: Walmart is moving from “land grab” to “make it profitable at scale.” Your biggest lever isn’t just targeting—it’s basket economics (AOV) and tighter efficiency thresholds.

Category performance: demand fundamentals beat platform mechanics

The benchmark signal is clear: the top categories weren’t top because of a hack. They were top because the demand behaves well.

Strong across both Amazon and Walmart:

  • Pet Supplies (repeat + replenishment demand; exceptionally high CVR)
  • Baby Products (needs-based, high intent)
  • Automotive (lower scale, unusually strong ROAS)
  • Health & Household (scale + stability—reliable allocator category)

Categories with repeat purchasing + high intent held up even as auctions tightened. In 2026, category benchmarks should function like guardrails: where incremental spend is likely to stay rational—and where it’s likely to leak margin.

Amazon deep dive: what the ad-type mix is telling you

Amazon’s ad ecosystem is behaving more like a mature media platform:

  • Sponsored Products: still the volume engine, but more sensitive to discipline as competition rises.
  • Sponsored Brands: increasingly “performance-capable,” not just awareness—often tied to higher AOV behavior.
  • Sponsored Display: best as a controlled retargeting lever; pulling back improved efficiency (a strong signal it punishes broad usage).
  • Sponsored Brand Video: grew fast, but costs are higher—its job is discovery; the win is converting that reach downstream.

In 2025, Amazon rewarded teams that treated ads like an operating system: capture demand (SP), shape consideration (SB/SBV), and reclaim leakage (SD retargeting). Brands that stayed overly bottom-funnel got trapped in the auction.

Walmart deep dive: the platform is getting more seasonal and more competitive

Walmart’s benchmarks show a market maturing quickly:

  • CPC rose steadily and spiked in Q4 (competition concentrates during peak weeks).
  • ACOS stayed stable most of the year, then spiked briefly in November and normalized as sales scaled.
  • AOV was flat most of the year but surged in November, despite being down 9% YoY overall.

Walmart now behaves like a channel where Q4 is not just bigger—it’s structurally different. The brands that win treat Q4 as a planned investment window, not an reactive scramble.

Seasonality: fewer windows matter more

On both platforms, 2025 performance concentrated into sharper peaks.

Amazon:

  • Early-year delivered efficient growth (double-digit YoY ad sales growth in Jan/Feb).
  • Prime Day period showed a clear lift (spend ↑ ~20–30% WoW, CVR lifted, ROAS temporarily improved).
  • Q4 delivered volume, but at higher competitive cost than 2024.

Walmart:

  • Q4 delivered the strongest weeks with improved CVR and temporary efficiency gains—despite higher CPCs.

Timing has become a real lever. In 2026, pacing decisions will separate teams that protect blended ROAS from teams that “buy” growth at the wrong moments.

What to do with this in 2026 (the short version)

Amazon priority: rebuild efficiency without sacrificing volume

  • Control CPC and query sprawl
  • Win on CVR + AOV improvements
  • Fund Prime Day and Q4 deliberately, not emotionally
  • Lean into efficiency-proven categories

Walmart priority: convert scale into sustainable efficiency

  • Tighten targeting to slow CPC creep
  • Rebuild AOV (bundles, pack sizes, merchandising)
  • Use upper-funnel formats deliberately, not broadly
  • Overweight Q4 when returns structurally improve

FAQ: Frequently Asked Questions from Amazon Performance in 2025

1) What’s the single biggest change from 2024 to 2025?

Efficiency became fragile. Growth was available, but the margin for error shrank—cost, conversion, and basket economics mattered more.

2) Why did Walmart ROAS fall ~18% if CVR increased?

Because returns weren’t constrained by conversion—they were constrained by economics: CPC rose (~11%) and AOV fell (~9%), and spend growth outpaced sales growth.

3) What does “Amazon rewards precision” actually mean in practice?

It means incremental budget is more sensitive to:

  • CPC control and bidding discipline
  • Query/targeting hygiene
  • SKU prioritization (stop funding low-margin noise)
  • Conversion and AOV improvements to offset auction inflation

4) Which categories are safest to scale based on the benchmarks?

Across both platforms, the data points to Pet Supplies, Baby Products, Automotive, and Health & Household as the most durable performers—driven by repeat demand and strong intent.

5) What’s the biggest planning mistake teams will make in 2026?

Treating Amazon and Walmart the same. The benchmarks show different maturity curves: Amazon requires precision to defend efficiency; Walmart requires converting scale into profitable economics—especially around Q4.

If you want, I can also turn this into a short “executive brief” version (same insights, tighter formatting) that sales can use as a pre-call send.