I’ve been running an SBV (Sponsored Brands Video) campaign targeting two competitor ASINs in auto parts. Over the last 8 months, I noticed a pattern that made me question whether there’s a bid threshold — below a certain point, your ads start pulling in broad, low‑quality traffic instead of your core keywords.
Curious if anyone else has seen this, or if I’m reading the data wrong.
The data timeline
September 2024 — Campaign launched. Bids around $2.65–2.77. Search terms were mostly the core product keyword (no “accessories” terms).
October — No changes. Still mainly core keyword.
November — I needed to lower ACOS, so I dropped bids by more than $0.50 over a short period. Search terms still looked fine — no “accessories” yet.
December — Dropped one ASIN’s bid by another $0.10. First “accessories” term appeared. Core keyword spend started dropping. I didn’t think much of it at the time.
January — Kept lowering bids (now below $2.00). More “accessories” terms started eating budget. Core keyword exposure kept falling.
February–March — Bids dropped further (down to $1.40–1.50). The campaign was now dominated by “accessories” long‑tail terms. Core keyword was barely getting impressions.
April — I ended the campaign. In the final weeks, “accessories” terms were spending more than ever.
What I think happened
My guess: once bids fall below a certain threshold, the system starts matching your ad to much broader, cheaper traffic pools. It’s not that the algorithm is wrong — it’s finding something that converts at that bid level, even if it’s not your core target. But once it starts feeding those broad terms, they crowd out your main keywords.
Also, core keywords are highly competitive. When you lower bids, you drop out of the auction for those terms. The system eventually learns that your ad performs on those broad terms and keeps pushing them, creating a loop that’s hard to break.
My questions for the community
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Has anyone else observed this with SBV product targeting? Is there really a “bid floor” below which your traffic quality drops off a cliff?
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If the damage is done, how do you claw back? Once your campaign is flooded with broad terms, is it salvageable?
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For SBV product targeting, is the only real way to control ACOS through better CTR/CVR, rather than bid adjustments?
Would love to hear from anyone who’s dealt with this.
Answers (5)
This matches a pattern I’ve seen across SP and SBV. There’s a bid floor for each keyword/ad combo. Drop below it and you’re pushed to cheaper, lower‑quality traffic. The challenge is that SBV product targeting doesn’t let you add negatives, so once the system starts feeding you broad terms, you have to pause the offending ASINs to stop the bleed.
Quick take: this is exactly why I stopped obsessing over ACOS on SBV campaigns. If you chase low bids, you get junk traffic. It’s better to find a stable bid that keeps you visible for your target terms, then focus on making your video and landing page convert better. The real lever is conversion rate, not bid.
Also, once a campaign gets flooded with broad terms, it’s very hard to reverse. I’ve had to restart campaigns fresh to reset the learning.
Another angle: it’s not just the bid — it’s relevance.
Your core keyword is highly relevant. At high bids, you win that auction. As you lower bids, you lose relevance for that term because others outbid you. But your ad is still “relevant” to broader terms like “accessories” — maybe because your product is genuinely related, or because the competitor ASIN you’re targeting has those terms in its listing.
Once you get a few sales on those broad terms, the system starts pushing them harder because it sees them as “working.” The feedback loop locks in.
To break it:
I think your hypothesis is correct — there is a bid threshold. Here’s why:
In Amazon’s ad auction, your ad rank = quality score × bid. If you lower your bid too much, you fall off the page entirely for competitive keywords. But your ad still exists, so the system starts testing it on lower‑cost, broader terms. Once it finds one that converts (even occasionally), it feeds that term more budget.
The problem is that those broad terms often have lower intent, so ACOS creeps up, but you’re stuck in a loop.
How to fix it:
It’s a systems game. You can’t just lower your way to profit.