Amazon’s Alleged Buy Box Algorithm Tweak Is Quietly Bleeding Seller Revenue

Something shifted on Amazon in the last two weeks of May 2026, and the seller community is only now piecing together what happened. Across Seller Central forums, private Slack groups, and at least two major agency war rooms, the pattern is the same: established FBA sellers with historically strong Buy Box ownership percentages are watching that number erode — sometimes by 15 to 22 percentage points — without any corresponding change to their pricing, inventory levels, or account health metrics.

Sources close to the matter say the culprit is an unconfirmed but increasingly suspected adjustment to the weighting logic inside Amazon’s Buy Box eligibility algorithm, specifically around how it scores “competitive price” relative to the broader market rather than just the listing itself. Amazon has not publicly acknowledged any change. A spokesperson declined to comment for this article.

What Are Sellers Actually Seeing in the Data?

The signal started appearing in Helium 10’s market tracker dashboards around May 22nd, according to multiple agency operators who monitor client accounts daily. Sellers in competitive, commoditized categories — home goods, pet supplies, kitchen tools — are disproportionately affected. Several Repricer.com and Feedvisor users report that even accounts running dynamic repricing tied to competitive benchmarks are getting suppressed.

One seven-figure home goods seller based in Austin, Texas, who asked not to be identified, said their Buy Box ownership on a flagship product dropped from 91% to 68% between May 20th and May 27th — with no price change, no new FBA competitors entering the listing, and no inventory gaps. “We literally changed nothing,” they said. “Our repricer was doing what it always does. It just stopped working.”

“What we’re hearing from multiple accounts is that Amazon may have recalibrated how it weights ‘competitive external pricing’ — meaning it’s now reportedly benchmarking your FBA price against third-party retailers like Walmart.com and Target.com more aggressively than before.” — James Dihardjo, Director of Marketplace Strategy at Tinuiti

💡 Article Summary

Key Insights

1

What Are Sellers Actually Seeing in the Data?

2

Is Walmart.com Pricing Now Factoring Into Amazon’s Buy Box Decisions?

3

Who Are the Alleged Winners Inside Amazon’s New Logic?

4

How Are Major Agencies Responding Right Now?

5

Is Amazon Preparing a Formal Policy Update — or Is This Intentional Opacity?

Source: Ecommerce Times

Dihardjo, who oversees Amazon channel strategy for a portfolio of mid-market and enterprise brands at Tinuiti, told Ecommerce Times he’s seen the pattern across at least nine client accounts in three separate categories. He called the situation “unconfirmed but structurally consistent.”

Is Walmart.com Pricing Now Factoring Into Amazon’s Buy Box Decisions?

This is the theory getting the most traction in agency circles right now. Amazon’s pricing crawlers have always monitored competitive retail prices externally — this isn’t new. But sources allege the weighting assigned to those external benchmarks has been meaningfully increased, possibly as Amazon’s competitive response to Walmart Marketplace’s accelerating GMV growth and the Commerce Department’s ongoing scrutiny of Amazon’s pricing parity policies.

The alleged practical effect: if your FBA-fulfilled product is priced at $34.99 on Amazon but available for $31.50 on Walmart.com — even from a different seller — Amazon’s algorithm may now be downgrading your Buy Box eligibility score, not suppressing the listing outright, but quietly reducing your win rate in rotation. It’s reportedly subtle enough that it doesn’t trigger any Seller Central notifications or policy warnings.

• Affected categories reportedly include: home & kitchen, pet supplies, sports & outdoors, and personal care
• FBM sellers in the same ASINs are reportedly not seeing equivalent suppression, which has some operators theorizing the change specifically targets FBA fee recovery margins
• Sellers running MAP-enforced brand registries appear less exposed, according to anecdotal reports from brand-side agency contacts
• Repricing tools like Informed.co, Aura, and BQool have not issued any formal guidance or algorithm-change alerts as of press time

Who Are the Alleged Winners Inside Amazon’s New Logic?

Counterintuitively, some sellers are seeing Buy Box improvements — and the pattern there is just as telling. Unconfirmed reports suggest that sellers who recently lowered prices to match or beat Walmart.com equivalent listings are seeing Buy Box percentages rise, in some cases dramatically. One private label seller in the fitness accessories space claimed their Buy Box ownership climbed from 74% to 89% after dropping their unit price by $2.80 — a move their account manager had recommended for unrelated reasons.

“If the theory holds — and I want to be clear it’s still a theory — then Amazon is essentially forcing sellers to treat Walmart.com as a price floor reference point, not just Amazon-internal competitors. That’s a significant structural shift for anyone running a multichannel pricing strategy.” — Liz Downing, VP of Seller Growth at Carbon6

Downing noted that Carbon6’s data science team is actively modeling the pattern across a broader seller dataset and may publish findings within the next two weeks. She declined to share preliminary numbers but described the signal as “statistically interesting enough to take seriously.”

How Are Major Agencies Responding Right Now?

The operational response at mid-market agencies is reportedly moving fast, even without official confirmation from Amazon. Sources at two unnamed Top 20 Amazon agencies say they’ve already quietly issued internal guidance to account managers to flag any Buy Box suppression events that occurred after May 18th and cross-reference them against external Walmart.com and Target.com pricing gaps.

Pattern89 and Jungle Scout’s Cobalt platform are both reportedly being used to pull competitive pricing benchmarks outside Amazon for the first time by agency teams that previously only ran intra-marketplace comparisons. Several operators are also reportedly revisiting their MAP enforcement strategies — particularly for brands that sell through multiple wholesale accounts that flow into Walmart’s marketplace via third-party resellers, creating price leakage they don’t fully control.

• Tinuiti has reportedly initiated a cross-channel pricing audit for affected brand clients
• Downstream Impact (a boutique Amazon agency based in Seattle) is allegedly advising clients to temporarily lower prices by 3-5% on affected ASINs as a diagnostic test
• At least one major consumer electronics brand has reportedly escalated to their Amazon Vendor Manager for clarification, with no response as of June 6th
• The Amazon Seller Forums thread on the topic has reportedly been reviewed but not responded to by Amazon moderators for 11 consecutive days

Is Amazon Preparing a Formal Policy Update — or Is This Intentional Opacity?

The silence from Amazon is itself generating frustration. Several sellers and agency operators note that Buy Box algorithm changes historically arrive without formal notice — Amazon has never been required to publish change logs for its ranking or eligibility systems. But the scale and consistency of what’s being reported this time is unusual enough that industry observers are watching closely for any hint of a formal acknowledgment.

One former Amazon marketplace policy manager, who spoke on background, said the pattern is “consistent with how Amazon tests pricing sensitivity interventions” — rolling out changes quietly to observe seller behavior before either expanding, rolling back, or formalizing them in policy documentation. “They’ve done this before with free shipping thresholds and with FBA fee exposure logic,” the former employee said. “The silence isn’t necessarily evasion. It might just be that they don’t know yet whether they’re keeping the change.”

“The uncomfortable truth for FBA sellers is that Amazon’s Buy Box has always been a black box. What’s different now is that the signals suggest the box got smaller — and multichannel operators with price inconsistency across platforms may be the ones paying for it.” — James Dihardjo, Tinuiti

What Should Sellers Do Before This Gets Confirmed?

Even without official confirmation, operators with significant Buy Box exposure should be taking diagnostic steps now. Based on conversations with agency leaders and tool vendors, the most actionable moves are:

• Audit your external price parity immediately: Pull your top 20 ASINs by revenue and compare your current Amazon price against Walmart.com, Target.com, and Chewy (if applicable). Any gap greater than 5-8% downward may be a risk factor under the alleged new weighting logic.
• Run a controlled price test on suppressed ASINs: Drop price by $2-3 on two or three affected listings for 72 hours and monitor Buy Box percentage in Seller Central’s Business Reports. The pattern should be visible within 48 hours if the theory holds.
• Flag the issue in your repricing tool’s support channel: Inform.co, Aura, and BQool should be aware — pressure from agency clients may accelerate any response or algorithm update on their end.
• Document everything with timestamps: If this becomes a formal policy change or a subject of regulatory scrutiny (the FTC has been watching Amazon’s pricing practices closely), having a paper trail of suppression events with corresponding pricing data will matter.
• Brief your brand’s Vendor or Account Manager in writing: Even if they don’t respond, the communication creates a record and occasionally surfaces internal information about what’s actually changing.

The broader implication — if the alleged algorithm shift holds and gets formalized — is significant for any brand running a multichannel pricing strategy. The longstanding practice of pricing slightly higher on Amazon to offset FBA fees while running promotions on Walmart or DTC may become a structural Buy Box liability rather than a routine margin management decision. For the thousands of mid-market sellers for whom Amazon Buy Box ownership is the primary lever on revenue, that’s not a minor adjustment. It’s a business model question.

We’ll be monitoring this closely. If you’re seeing suppression events consistent with what’s described here, contact our editorial team.