Amazon Agency KPIs: Metrics That Matter

You're paying an agency $15,000 a month to manage your Amazon business. Every month you get a report. It shows ACoS improved from 23% to 21%. The agency celebrates. You approve another month.

Six months later, revenue is flat. You're spending 30% more on ads. Organic sales are down. You don't know why because the report never showed organic sales.

That agency fired you, not the other way around.

Most Amazon agency reports are designed to obscure underperformance. They show efficiency metrics (ACoS improved!) without growth context. They blend branded and non-branded performance to hide poor acquisition. They report ad-attributed sales without showing what happened to the organic business.

If you're evaluating an Amazon agency or trying to hold your current partner accountable, here's the framework: the metrics that reveal whether your agency is building durable growth or just managing spend, the red flags that signal they're hiding the full picture, and the practical scorecard you can use in your next monthly review.

Why Most Amazon KPI Dashboards Miss the Point

The problem with vanity metrics in agency reporting

ACoS (Advertising Cost of Sale) is the metric every agency leads with. It's clean, it's simple, and it's almost meaningless by itself.

ACoS tells you what percentage of ad-attributed sales went back into ad spend. It doesn't tell you:

Whether total sales grew or shrank
Whether organic sales declined while ad sales increased
Whether the agency is buying expensive non-branded keywords or just harvesting cheap branded clicks
Whether you're acquiring new customers or re-marketing to existing ones
Whether the efficiency gain came from strategic optimization or cutting growth spend

An agency can improve ACoS by cutting non-branded campaigns, reducing bids on high-volume keywords, or shifting budget entirely to branded terms. All of those moves make the efficiency number look better while killing growth.

What a complete agency performance picture looks like

A good agency report answers three questions:

Are we growing? (Total sales trend, new customer acquisition, market share movement)
Are we profitable? (TACoS, contribution margin, payback period on acquisition spend)
What did the agency actually do? (Input metrics: campaigns launched, content updated, tests run, keyword targeting refined)

If your monthly report answers question 1 and 2 but not 3, you're paying for results you can't attribute to the agency's work. If it answers 3 but not 1 and 2, you're paying for activity that doesn't connect to outcomes.

The metrics below form the minimum viable accountability framework. Any agency unwilling to report on all of them is either unsophisticated or hiding something.

The KPIs Your Amazon Agency Should Report On Every Month

KPI #1

TACoS (Total Advertising Cost of Sale)

What it is: Ad spend divided by total sales (ad-attributed + organic), not just ad sales.

Why it matters for agency evaluation: TACoS is the single most important health metric because it shows whether your agency is driving net growth or just shifting where sales come from.

Scenario 1: ACoS stays at 25%. TACoS drops from 15% to 12%. Your agency is successfully driving organic growth alongside paid. Ad spend is staying efficient while the total business scales. This is what good looks like.

Scenario 2: ACoS drops from 25% to 20%. TACoS increases from 15% to 18%. Your agency made the efficiency metric look better by cutting growth spend, but total sales declined because organic dropped faster than ads improved. You're now spending a higher percentage of revenue on ads to get fewer total sales.

The red flag: If your agency doesn't report TACoS, they either don't understand this distinction or they're hiding declining organic performance. TACoS is not a native Amazon metric — it has to be calculated manually or via third-party tools. An agency that doesn't track it is not operating at a sophisticated level.

What good looks like: TACoS trends matter more than absolute numbers. For established products in moderate-competition categories, 8–15% is a reasonable range. For new product launches, 25–40% may be expected temporarily. The critical signal is the trend direction over 3–6 months.

KPI #2

ACoS Segmented by Campaign Type (Branded vs. Non-Branded vs. Category)

What it is: Advertising Cost of Sale broken out by whether the keyword/audience is branded (contains your brand name or ASIN), non-branded (generic product or category terms), or competitive/category conquest.

Why it matters for agency evaluation: An agency reporting blended ACoS is hiding the full story. Branded campaigns typically run at 5–15% ACoS because the shopper already intended to buy your product. Non-branded campaigns (which drive incremental new customers) may run at 25–50% ACoS because you're competing for attention against alternatives.

If your agency shows a blended 18% ACoS, it could mean:

Interpretation A: Branded: 8% ACoS, 70% of spend (efficient but not growth-driving) — Non-branded: 45% ACoS, 30% of spend (expensive acquisition, possibly unprofitable)

Interpretation B: Branded: 12% ACoS, 40% of spend — Non-branded: 22% ACoS, 60% of spend (good acquisition efficiency, healthy growth mix)

The blended number looks identical. The underlying business health is completely different.

The red flag: If your agency won't segment branded vs. non-branded, they're likely hiding poor acquisition performance behind efficient branded spend.

What to ask: "What percentage of our ad spend is going to branded vs. non-branded campaigns, and what's the ACoS for each?" Follow up: "What's our month-over-month trend in non-branded impression share?"

KPI #3

New-to-Brand (NTB) Percentage and Customer Acquisition Cost (CAC)

What it is: The percentage of ad-attributed sales that came from customers who haven't purchased from your brand in the past 12 months, and the cost to acquire each new customer.

Why it matters for agency evaluation: New-to-brand percentage tells you whether your agency is building your customer base or just re-marketing to existing buyers. If NTB is declining, your agency is increasingly dependent on repeat purchases, which limits growth ceiling.

CAC (calculated as ad spend divided by new customers acquired) tells you the unit economics of acquisition. If CAC is rising faster than customer lifetime value (LTV), you're burning money.

What good looks like: NTB percentage varies by product type and purchase frequency. For consumables with high repeat rates, 30–50% NTB is healthy. For durable goods, 70–90% NTB is expected. The trend matters most: if NTB is declining month-over-month, your agency is not effectively reaching new customers.

The red flag: If your agency has never mentioned new-to-brand metrics, they're either not tracking them (a competence issue) or they're seeing declining NTB and don't want to report it.

Amazon data source: New-to-brand metrics are available in the Amazon Ads console for Sponsored Products, Sponsored Brands, and Sponsored Display campaigns. If your agency says they can't access this data, they're either lying or using an Amazon Advertising account that predates the feature rollout (unlikely in 2026).

KPI #4

Organic Sales Growth Alongside Paid

What it is: The trend in sales not attributed to advertising (organic search, repeat buyers, external traffic) reported alongside ad sales.

Why it matters for agency evaluation: A good agency doesn't just manage ad spend. They improve product discoverability, listing quality, conversion rates, and customer satisfaction. All of these drive organic sales.

If your organic sales are declining while ad sales increase, it signals:

The agency is cannibalizing organic sales with paid (bidding on keywords you already rank for organically)
Product ranking is declining (keyword optimization, A+ content, review velocity are being neglected)
Conversion rate is dropping (listing quality is stagnant or regressing)

The scenario brands miss: Agency increases ad spend by 30%. Ad-attributed sales grow 25%. The agency reports growth. But organic sales declined 15% during the same period, and total revenue is flat or down. The agency is replacing free sales with paid sales and claiming credit for growth.

What good looks like: For established products, organic sales should hold steady or grow alongside paid. For product launches, organic sales should ramp as the product gains ranking and reviews. If organic declines while paid increases, something is structurally wrong.

How to get this data: Amazon's Business Reports show total sales. Amazon Ads reporting shows ad-attributed sales. Organic sales = total sales minus ad-attributed sales. If your agency isn't reporting this split, you're flying blind.

KPI #5

Share of Voice Trends for Target Keywords

What it is: The percentage of total impressions your brand captures for high-priority search terms, tracked over time.

Why it matters for agency evaluation: Share of voice (SOV) is a leading indicator. If your SOV is increasing for target keywords, your agency is gaining market position. If SOV is declining, you're losing ground to competitors even if absolute sales hold steady (because the category is growing and you're not keeping pace).

How it's measured: Amazon's Search Query Performance (SQP) report (available through Brand Analytics) shows impression share, click share, and purchase share for specific search terms. Third-party tools (Helium 10, Jungle Scout, Perpetua) also track SOV.

A sophisticated agency should be tracking SOV for:

5–10 high-volume category keywords
Your branded terms
Competitor branded terms (if running conquest campaigns)

What good looks like: SOV should be stable or increasing for priority keywords. If SOV drops below 10% for a previously strong keyword, your agency needs to diagnose why (lost Buy Box, ranking drop, increased competitor spend, content quality decline).

The red flag: If your agency has never discussed share of voice, they're not thinking strategically about competitive positioning. They're optimizing individual campaigns in isolation rather than managing your brand's overall market presence.

KPI #6

Incremental ROAS (Return on Ad Spend)

What it is: The revenue gain specifically attributable to the advertising, isolating for sales that would have happened anyway.

Why it matters for agency evaluation: Standard ROAS (revenue divided by ad spend) overstates the value of advertising because it includes sales that would have occurred organically. Incremental ROAS measures the lift from advertising.

Example: You spend $10,000 on ads and generate $50,000 in ad-attributed sales. Standard ROAS = 5x. But if you had turned off all ads, you still would have made $40,000 in organic sales. Incremental revenue = $10,000. Incremental ROAS = 1x. The advertising barely broke even.

How it's measured: The gold standard is a holdout test (geo-split or time-based, turning ads off for a control group). Amazon Marketing Cloud (AMC) enables more sophisticated incrementality modeling. Third-party tools can estimate incrementality using historical data.

The reality: Most agencies don't report incremental ROAS because it makes the advertising look less effective. If your agency mentions incrementality at all, they're operating at the top tier. If they claim a 5x ROAS without discussing how much of that would have happened organically, they're inflating their value.

What good looks like: For branded campaigns, incremental ROAS is often below 2x because many of those customers would have found you anyway. For non-branded campaigns in competitive categories, incremental ROAS of 2.5–4x is strong. If your blended incremental ROAS is below 1.5x, you're spending more to acquire sales than they're worth.

Beyond Advertising: Operational KPIs That Reveal Agency Quality

If your agency positions itself as full-service (not just PPC management), these operational metrics belong in the monthly report. They reveal whether the agency is actively managing the health of your Amazon business or just running ad campaigns.

Catalog Health Metrics

Listing Quality Scores: Amazon provides listing quality scores (0–10) in the Brand Dashboard. A strong agency maintains 9+ scores across the catalog by keeping content fresh, images high-quality, and all required attributes filled.

A+ Content Coverage: What percentage of your catalog has A+ Content? Brand Story? Updated Enhanced Brand Content? These content assets improve conversion rate and organic ranking. An agency that never mentions content coverage is neglecting a major growth lever.

Search Term Indexing: Are your priority keywords actually indexed on your product pages? If a high-volume keyword isn't indexed, Amazon won't show your product for that search. A good agency runs indexing checks and adds missing keywords to backend search terms or content.

Inventory Performance

Inventory Performance Index (IPI): Amazon scores sellers 0–1000 based on excess inventory, sell-through rate, stranded inventory, and in-stock rate. IPI below 400 risks storage limits and higher fees. If your agency coordinates with logistics, IPI trends should be in the report.

Stockout Rate: How often did your bestsellers go out of stock? Stockouts kill organic ranking and waste ad spend (you pay for clicks on products customers can't buy). A competent agency forecasts inventory needs and flags risk before it becomes a stockout.

Account Health

Order Defect Rate (ODR): Must stay below 1% to avoid account suspension. If your agency manages customer service or listing compliance, ODR is their responsibility.

Policy Compliance: Has Amazon flagged any listings for restricted claims, missing compliance docs, or policy violations? These issues kill sales. A strong agency monitors the Account Health dashboard and resolves violations immediately.

The Red Flags: KPIs Your Agency Might Be Hiding

Red flag 1: Reporting ACoS without TACoS context. This is the most common obfuscation tactic. If your agency shows improving ACoS but never mentions total sales or TACoS, they're hiding the organic sales story. Demand both metrics in every report.

Red flag 2: No segmentation between branded and non-branded performance. A blended ACoS number is almost always hiding something. Agencies do this because branded campaigns are easy to run efficiently (low-hanging fruit) and make the blended number look good. Force the segmentation.

Red flag 3: Ignoring organic sales trends. If the report only covers ad metrics and never shows the trend in non-ad-attributed sales, the agency is either (a) not sophisticated enough to track it or (b) deliberately avoiding it because organic is declining.

Red flag 4: No discussion of new-to-brand percentage or customer acquisition. An agency focused only on efficiency (ACoS/ROAS) and not growth (new customers, market share) is optimizing for the wrong objective. If NTB never appears in your reports, ask why.

Red flag 5: No documented input metrics. If you ask "What did you actually do this month?" and the agency can't point to specific campaigns launched, keyword targeting refined, A+ Content updated, or tests run, you're paying for results that may have nothing to do with their work. Good agencies report both inputs (what they did) and outputs (what resulted).

Red flag 6: Absent attribution beyond last-click. Amazon's default attribution is last-click within a 7-day window. This undercounts the value of upper-funnel campaigns (Sponsored Brands, DSP, video ads). If your agency never mentions attribution models or multi-touch contribution, they're underselling their impact or they're not running upper-funnel campaigns at all.

Red flag 7: No margin or profitability metrics. ACoS and ROAS are revenue efficiency metrics. They don't account for your product's margin. A 25% ACoS might be profitable on a 50% margin product and disastrous on a 30% margin product. If your agency doesn't discuss contribution margin or profit per order, they're optimizing for revenue growth that might not be profitable.

How to Build an Agency KPI Scorecard

Here's the practical monthly review framework you can use with any Amazon agency:

Core Metrics (Report Every Month)

Metric	What It Tells You	Red Flag Threshold
Total Sales (ad + organic)	Overall business growth	Flat or declining for 2+ months
TACoS	Ad spend as % of total revenue	Increasing while ACoS holds steady or improves
ACoS (blended)	Overall ad efficiency	Improving while total sales decline
ACoS (branded vs. non-branded)	Acquisition efficiency	>70% of spend on branded terms
New-to-Brand %	Customer acquisition health	Declining MoM for 3+ months
Organic Sales Trend	Durability of non-ad growth	Declining while ad sales increase
Share of Voice (top 5 keywords)	Competitive positioning	Loss of 5+ pts on priority keywords

Input Metrics (Report What the Agency Actually Did)

Category	Examples	Why It Matters
Campaign Structure	New campaigns launched, campaign types tested (SB Video, DSP, etc.)	Signals proactive testing vs. set-it-and-forget-it
Keyword Optimization	Keywords added, negatives applied, search term harvesting	Shows active bid and targeting refinement
Content Updates	A+ Content updated, Brand Store pages added, listing copy refreshed	Investment in conversion rate and organic ranking
Testing Activity	A/B tests run, bid strategy experiments, audience tests	Continuous improvement vs. static management

Monthly vs. Quarterly Review Cadence

Monthly: Core performance metrics (sales, TACoS, ACoS segmentation, NTB%, organic trend). Input metrics (what the agency did). Surface any red flags immediately.

Quarterly: Deeper strategic review. Share of voice trends, catalog health scores, incrementality analysis, profitability by product line, year-over-year growth vs. category benchmarks.

Questions to Ask in Every Agency Performance Review

"What's our TACoS trend over the past 3 months? How does that compare to ACoS trend?"
"What percentage of our ad spend is branded vs. non-branded? What's the ACoS for each?"
"What happened to our organic sales this month compared to last month?"
"What's our new-to-brand percentage, and is it increasing or decreasing?"
"What did you actually do this month? Show me the campaigns launched, keywords added, content updated."
"Which of our priority keywords are we losing share of voice on, and why?"

If your agency can't answer these questions with specific data, you don't have an accountability problem. You have a competence problem.

What Good Agency Reporting Actually Looks Like

A strong monthly agency report includes:

Executive Summary (1 page):

Total sales (ad + organic) vs. prior month and prior year
TACoS and ACoS trends
Key wins and key concerns flagged immediately
Top 3 strategic recommendations for next month

Performance Metrics (2–3 pages):

Sales breakdown (ad-attributed vs. organic)
ACoS segmented by branded / non-branded / category
New-to-brand percentage and trend
ROAS by campaign type
Top 10 performing and underperforming ASINs

Activity Summary (1 page):

Campaigns launched or paused
Keywords added and negative keywords applied
Bid adjustments and budget changes
Content updates (A+ Content, Brand Store, listing copy)
Tests launched and results

Strategic Context (1 page):

Share of voice movement for priority keywords
Competitive activity observed
Upcoming inventory needs or promotional plans
Recommended tests or campaigns for next month

How SupplyKick Approaches Client KPI Reporting

At SupplyKick, we built our reporting framework around the TACoS principle: are we driving net growth or just shifting where sales come from? Every monthly report shows total sales, ad sales, and organic sales side by side. We segment ACoS by branded, non-branded, and category conquest. We track new-to-brand percentage and flag when it declines. We document what we actually did (input metrics) so clients can see the connection between activity and outcomes.

We also report operational metrics beyond advertising because we position as full-service: IPI scores, listing quality scores, A+ Content coverage, stockout incidents. If we're managing the whole Amazon business, we're accountable for the whole picture — not just the ad dashboard.

This transparency is why SupplyKick maintains 96% partner retention. Clients stay when they can see exactly what they're paying for and how it connects to growth.

Want an Agency That Reports the Full Picture?

SupplyKick reports TACoS, organic trends, NTB%, and input metrics in every monthly review. No hidden data.

Connect with Our Team

FAQ: Amazon Agency KPIs

What is a good TACoS for Amazon?

TACoS (Total Advertising Cost of Sale) varies by product category, margin structure, and business stage. For established products in moderate-competition categories, 8–15% TACoS is typical. For new product launches, 25–40% TACoS is common in the first 3–6 months as you invest in customer acquisition. The absolute number matters less than the trend: TACoS should decline over time as organic sales grow and ad spend stabilizes.

How often should my Amazon agency report performance?

Monthly reporting is the standard for Amazon agencies. A monthly report should include sales trends (ad + organic), TACoS and ACoS segmentation, new-to-brand percentage, and a summary of what the agency actually did (campaigns launched, keyword targeting refined, content updated). Quarterly reviews should go deeper: share of voice trends, incrementality analysis, catalog health, and profitability by product line.

What's the difference between ACoS and TACoS?

ACoS (Advertising Cost of Sale) measures ad spend as a percentage of ad-attributed sales only. TACoS (Total Advertising Cost of Sale) measures ad spend as a percentage of total sales (ad + organic). TACoS is a better indicator of overall business health because it shows whether your agency is driving net growth or just replacing organic sales with paid sales. ACoS can improve while TACoS worsens if organic sales decline.

How do I know if my Amazon agency is underperforming?

Red flags include: (1) Reporting ACoS without showing TACoS or total sales context. (2) No segmentation between branded and non-branded campaign performance. (3) Declining organic sales while ad sales increase. (4) Decreasing new-to-brand percentage over multiple months. (5) No documentation of what the agency actually did (input metrics). (6) Inability to answer "What's our share of voice trend for our top keywords?" If your agency can't provide clear answers on these points, you have a competence or transparency problem.

The Bottom Line

Most Amazon agencies report metrics that make their work look good. A few agencies report metrics that show whether the business is actually growing.

The difference comes down to transparency. Is your agency willing to show TACoS alongside ACoS? Segment branded vs. non-branded performance? Report organic sales trends even when they're declining? Track new-to-brand percentage even when it's dropping? Document what they actually did each month, not just the results?

If your agency resists any of these metrics, you don't need better KPIs. You need a better agency.

Talk to SupplyKick about what transparent marketplace strategy and accountability looks like.

Amazon Agency KPIs: The Metrics That Actually Matter for Measuring Agency Performance