Published: 15th August 2026
A campaign can appear healthy in Amazon Ads while quietly damaging the P&L. Sales are coming through, budgets are being spent and total revenue may even be rising. But if spend is growing faster than profitable sales, the account is not scaling. It is leaking. So, why are Amazon campaigns overspending? Usually, it is not one bad keyword or an isolated bid. It is a lack of control across targeting, bids, budgets, conversion and measurement.
For GB brands, the warning signs are familiar: ACoS rises without a clear growth plan, campaigns run out of budget before the strongest trading hours, branded traffic absorbs spend that would have converted anyway, and supposedly efficient activity fails to produce incremental profit. Amazon PPC does not overspend by accident. It overspends when campaign architecture and commercial targets are not directing every optimisation decision.
Amazon gives advertisers many ways to buy visibility, but it does not know your true margin, stock position, repeat purchase rate or commercial priorities unless you build those constraints into the account. Its default incentives favour delivery. Your job is to make delivery profitable.
The most common issue is treating ACoS as the only performance metric. A 25% ACoS can be excellent for a high-margin product, unacceptable for a low-margin item, or strategically sensible during a launch. Without a target that reflects contribution margin, VAT, fulfilment fees, promotions and returns, a campaign can look efficient in the advertising console while losing money in reality.
Overspending also accelerates when decisions are made campaign by campaign instead of at account level. One Sponsored Products campaign may look controlled, but overlap with an automatic campaign, a product targeting campaign and a Sponsored Brands campaign can mean you are bidding against yourself for the same shopper. The account spends more without earning proportionately more demand.
Broad targeting is not inherently wasteful. It is useful for discovering search terms, supporting category reach and giving Amazon enough data to find converting shoppers. The problem begins when discovery and scale are mixed together with no boundaries.
Automatic campaigns, broad match and loose product targeting should have a defined role. They are research engines. If converting terms found there are never moved into tightly controlled exact-match campaigns, the brand keeps paying the discovery premium indefinitely. The same high-intent search terms may then trigger in several places, each with different bids and no clear owner.
A well-governed account separates exploration from exploitation. Exact match campaigns protect proven terms and allow precise bidding. Phrase and broad match campaigns find new variation. Auto campaigns identify customer language and ASIN opportunities. Product targeting reaches relevant competitor and category pages. Each layer needs a different target, bid range and negative keyword strategy.
Negative targeting is where many accounts lose discipline. Search terms that have spent beyond an agreed threshold without producing sales should be reviewed quickly, not left to accumulate for weeks. Equally, a term that converts well in an exact campaign should usually be negated from broad or auto activity if that overlap is pushing up the cost of winning the same auction.
A monthly review is too slow for an account with meaningful spend. The right cadence depends on traffic volume, but high-spend search terms, sudden ACoS movement and budget exhaustion need attention weekly or more often. The objective is not to cut every non-converting term immediately. Amazon attribution has a lag, and some products need more clicks before a decision is statistically useful. The objective is to stop unproven spend becoming permanent spend.
A high bid is not automatically a bad bid. If a keyword produces profitable orders and contributes to organic ranking on a strategically important term, paying more may be justified. The issue is bidding without knowing what a click is worth.
Start with the commercial target. If a product sells for £30 and your maximum viable ACoS is 20%, the maximum allowable advertising cost per order is £6. If that keyword converts at 10%, it can support a £0.60 cost per click before reaching the target. That calculation is not a reason to set every bid at £0.60. It is a guardrail for deciding where bids can rise, where they must fall and where conversion is the real problem.
Many brands rely on Amazon’s suggested bids or apply the same bid logic across every product. Suggested bids reflect auction conditions, not your margin. A £1.20 bid may be appropriate for a hero SKU with strong conversion and room for customer acquisition. It can be destructive for a variant with weak reviews, low stock or a narrow contribution margin.
Placement multipliers create another hidden source of overspend. Top of Search often converts better, but adding aggressive placement adjustments without reducing base bids can make the effective bid far higher than intended. Review performance by placement, not just at campaign level. If Top of Search is profitable, invest deliberately. If it is simply expensive, do not mistake visibility for progress.
Budget caps are a pacing tool, not a profitability strategy. Raising a daily budget because a campaign is running out of money simply allows it to spend more. First establish whether that campaign deserves a bigger share of the account budget.
The strongest campaigns are not always those with the lowest ACoS. A branded campaign can show excellent efficiency while capturing shoppers who were already searching for your brand. A non-brand campaign may have a higher ACoS but generate genuinely incremental new-to-brand demand. The commercial question is where the next pound of spend will create the best marginal return.
Budget allocation should reflect business priorities: profitable hero products, launches with a defined investment case, seasonal ranges, stock that needs to move and terms where the brand can win meaningful visibility. It should not be determined by whichever campaign happens to spend fastest at 9am.
This is particularly relevant during peak trading periods. Raising budgets across the board ahead of Prime events, Black Friday or Christmas is not a plan. Campaigns should be prepared with bid rules, stock checks, promotional alignment and clear thresholds for intervention. Otherwise, increased shopper traffic merely amplifies the account’s existing waste.
Advertising can buy a click. It cannot fix a weak product detail page. When conversion falls, brands often respond by cutting bids or changing targeting. That may reduce spend, but it does not address why shoppers are leaving.
Price competitiveness, review rating and volume, main image quality, title clarity, variation structure, Buy Box ownership, delivery promise and stock availability all influence conversion. A campaign sending qualified traffic to a poor listing will overspend because it has to buy too many clicks to generate an order.
Look for differences between traffic and conversion. If impressions and clicks rise while conversion declines, investigate the offer and the search terms being matched. If conversion is stable but ACoS rises, rising CPC or placement mix may be the cause. If both sales and traffic fall, stock, eligibility, retail readiness or competitive pressure may be limiting delivery. These are different problems and they need different actions.
Sponsored Brands and Sponsored Display deserve the same commercial scrutiny. They can support brand defence, consideration and retargeting, but they are not exempt from accountability because they sit higher in the funnel. Define the job of each campaign before judging it. A retargeting campaign should be assessed differently from a category conquesting campaign, yet both need a ceiling on acceptable cost and a route to profitable growth.
Amazon’s reporting is valuable, but it is not the whole business. Attribution windows can make campaigns appear more effective than they are, especially where branded search, repeat customers and multiple ad formats are involved. A sale may be attributed to the final ad interaction even when the shopper had already been influenced by organic rank, email, social activity or another Amazon campaign.
That does not mean you should distrust the platform. It means you should triangulate. Compare advertising results with total sales, organic sales share, unit session percentage, branded versus non-brand mix, stock movement and contribution margin. Watch what happens when spend increases or decreases. If paid sales grow but total sales remain flat, the account may be cannibalising organic demand rather than creating incremental revenue.
A mature PPC strategy also considers the product lifecycle. During a launch, higher ACoS may be a planned cost of generating reviews, relevance and early sales history. Once a product is established, the same level of spend may no longer be justified. Targets should change as the commercial purpose changes.
The answer is not to pause everything with a high ACoS. Cutting too aggressively can damage ranking, reduce sales velocity and hand competitors valuable placements. The answer is a disciplined operating rhythm that makes spend accountable.
Set product-level profitability targets before setting campaign targets. Build campaign structures that separate discovery, scale, brand defence and product targeting. Audit search-term overlap. Set bid and placement rules based on conversion and margin. Reallocate budgets towards campaigns that produce profitable, incremental growth. Then review performance against the wider retail picture, not an isolated advertising dashboard.
For brands spending meaningful sums each month, this requires senior ownership. It is strategic work with operational consequences, not a once-a-month reporting exercise. Accendo360 approaches Amazon advertising as part of the marketplace P&L, connecting campaign decisions to margin, retail readiness, stock and growth priorities.
The useful question is not whether a campaign spent its budget. It is whether every additional pound bought profitable momentum for the brand. Build the account around that standard, and Amazon PPC becomes easier to scale without letting spend take control.