I’ve been selling on Amazon for 5 years, and one of the most common wasted expenses I see sellers make is completely avoidable: internal ad competition. Most don’t even realize it’s happening until their budget is gone and their sales haven’t moved.

Two weeks ago, I helped a friend go through his home goods ad account. He’d spent $8,000 on ads that month, and his Advertising Cost of Sales (ACoS) had hit 65% out of nowhere. When I dug into his campaign setup, I found he was running the same core keyword across 5 separate ad campaigns. That meant 5 of his own ads were bidding against each other for the same traffic, driving up his costs and wasting most of his budget before any customers even saw his listings.

Internal ad competition, or ad cannibalization, happens when multiple campaigns, ad groups, keywords, or ASINs within the same seller account have overlapping targeting settings. They all enter the same auction for a given user search, end up driving up your own Cost Per Click (CPC), eating into your budget, and dragging down overall conversion rates because only a handful of ads ever get shown to the customer.

Amazon’s ad system only allocates a limited number of ad slots for any single search query. Even if multiple of your ads meet the eligibility requirements for that search, the algorithm will only pick 1 or 2 top-performing ads to show. The rest of your bids just end up driving up the price you pay for the slot you do win, without any extra exposure to show for it.

If you notice any of these signs, there’s a good chance your ads are competing with each other:

  • One of your campaigns sees a sudden, unexplained drop in impressions, even after ruling out category-wide promotions, competitor pricing changes, or policy updates

  • Your CPC has climbed steadily for a week, but your Click-Through Rate (CTR) and Conversion Rate (CVR) are both trending down, with no obvious external cause

  • When you pull your ad reports, the same keyword shows conversion data across 3 or more ad groups, with no single campaign driving the majority of results or holding a stable rank for that term

  • Your automatic ad campaigns start serving consistently for core keywords you’re already prioritizing in your manual campaigns

  • Multiple ad groups are targeting the exact same competitor ASIN, with bids creeping higher and higher as you try to outperform… yourself

A question I get all the time is: if I target the same keyword in two different campaigns, each set to focus on different ad positions, will they still compete? I ran a dedicated test for this exact scenario a few months back when I was selling backdrop curtains.

I set up two Sponsored Products (SP) campaigns targeting the same core term: one had a 100% bid adjustment to prioritize Top of Search placement, and the other ran at a standard bid to target Rest of Search and product detail page slots. I thought I was covering more ground to capture extra traffic, but after a week, the numbers told a different story: my CPC had jumped from $1.20 to $2.70, my CVR dropped from 7% to 4%, and my ACoS blew past 70%.

I merged the two campaigns into one, kept all the same targeting but managed the keyword in a single ad group with a separate bid adjustment for Top of Search placement. Two weeks later, the data had fully recovered: my CPC was back down to $1.40, my CVR bounced back to 8%, and my ACoS dropped by 20 percentage points overnight.

The logic is simple: even if you set different placement targets, any campaign targeting the same keyword is competing for the same user search intent. Amazon’s algorithm pools all eligible ads together to pick the best ones to show, regardless of their placement settings, so you’re still bidding against yourself at the end of the day.

These are the methods I’ve used for 3 years that fix 90% of internal ad competition issues

  • Keep each unique keyword in only one ad campaign. No matter if you’re running broad, phrase, or exact match for that term, manage them all in the same ad group instead of spreading them across campaigns. I’ve tested this extensively, and running multiple match types in the same group doesn’t cause internal competition. The algorithm will prioritize the best match for each search query, and there’s no negative impact on impressions

  • When you pull a high-performing core keyword from an automatic campaign to add to a manual campaign, add that term as an exact negative match in the automatic campaign to avoid overlapping bids for the same traffic

  • Use a clear, consistent naming convention for all your campaigns, so you can tell what each one is targeting at a glance, no need to click through settings to spot duplicate targeting

The naming system I use is simple, and it’s worked across every category I’ve sold in: [product line] + [variant attribute] + [ad type] + [manual/automatic] + [targeting focus] + [core goal] + [match type] + [bidding strategy] + [launch date].

For example, if I’m running a manual SP campaign for blue iPhone 15 cases, targeting color-related core keywords to drive new traffic, using phrase and exact match with fixed bids, launched on August 19, the campaign name would be: “iPhone15 Case Blue + SP + Manual + Color Core Terms + Traffic Expansion + Phrase/Exact + Fixed Bid + 0819”. I can scan all my campaign names in seconds to see what each group is for, and spot any overlapping targeting right away.

For a campaign focused on stealing traffic from competitors, the name would be: “iPhone15 Case Blue + SP + Manual + Competitor ASIN Targeting + Share Grab + Exact + Top Fixed Bid + 0819”. The goal is clear here: I want to take sales from competing listings, so I don’t hold it to the same ACoS targets as my traffic expansion campaigns, and I never accidentally mix up its targeting with my other ad groups.

One common myth I want to clear up: a lot of sellers worry that running all three match types for the same keyword in a single ad group with the same bid will cause internal competition. I’ve run dozens of tests on this, and there’s no noticeable impact on impressions. The algorithm will prioritize broad match first for relevant searches, and there’s no significant difference in how it impacts your Sales Per Click (SPR) either. No need to split those out into separate groups unless you have a specific testing goal.

Have you ever dealt with unexpected ad spend that you couldn’t explain? What’s the biggest ad issue you’re troubleshooting right now? Drop a comment below, I’ll help you work through it.