Amazon SEO Has Changed. If Your TACOS is Rising, This Might Be Why
If your TACOS is creeping up, and a growing % of your sales are coming from ads rather than organic, here’s the uncomfortable truth:
It might not be your bids. Or your budgets. Or even your product.
It might be COSMO.
COSMO is Amazon’s new AI-driven intent engine, and it’s already live, influencing search relevance, ranking, and navigation behind the scenes.
Launched quietly and tested across 10% of Amazon’s U.S. traffic in mid‑2024, COSMO is now fully deployed (as of July 2025) across Amazon’s core systems.
And it changes everything we know about how organic ranking works.
Why you’re spending more to get the same visibility
Let’s break this down.
Before COSMO, Amazon’s A9 algorithm ranked products based primarily on:
Keyword match
Click-through rate
Conversion rate
Sales velocity
A strong organic rank was earned by optimising for literal search-term relevance. If you knew how to write a high-converting, keyword-rich listing and back it up with decent performance, you could dominate page one.
Now? That’s no longer enough.
COSMO changes Amazon’s search engine from keyword-matching to intent-matching.
This means:
Your product must not only match the words a customer types…
It must align with why they’re typing them.
What is COSMO, and how does it work?
COSMO (Commonsense-based Semantics for Modeling Objectives) is trained on millions of real Amazon behaviours - search, click, and buy patterns - and builds a semantic understanding of what shoppers are really looking for.
Example from the paper:
Search: “shoes for pregnant women”
COSMO infers intent: “needs slip-resistant, comfortable shoes”
Ranks: “non-slip trainers” — even if the product doesn’t mention pregnancy
This semantic leap is what makes COSMO so powerful - and so disruptive.
It doesn’t just scan for matching keywords. It reads between the lines.
So what’s the impact on organic rank?
If your product doesn’t semantically match the intent behind a query - even if it includes the right keywords, your listing can be invisible on the search results page.
This leads to:
Declining organic visibility
Increased reliance on paid traffic
Rising TACOS
Shrinking margins
And this is happening even to high-performing brands.
COSMO is rewarding relevance over literalness - and punishing listings that don’t reflect real-world use cases, occasions, or emotional triggers.
What does Amazon consider “relevant” now?
According to the COSMO paper, listings are ranked higher when they align with:
Who the product is for
Why they’re shopping
What job (function or need) the product is solving
How the product fits into an occasion or lifestyle
It uses a combination of:
Search-buy mapping
Semantic language modelling
Image understanding
Session behaviour data
COSMO then generates “common sense” links between products and customer objectives — allowing Amazon to show shoppers what they mean, not just what they say.
What does this mean for your SEO strategy?
The brands who win in this new landscape are those who shift their mindset.
From: “What keywords should we rank for?” To: “What emotional or situational intent does our product best fulfil?”
Here’s what you need to be doing:
🔹 Optimise for context, not just copy Explain who your product is for, when it's used, what need it solves, and how it makes the customer feel.
🔹 Use images with emotional and situational cues COSMO leverages visual semantics. Flat white backgrounds and spec-led imagery won’t cut it. Use lifestyle photography that signals intent.
🔹 Write like a human, not a bot Natural language that reflects real behaviour and emotional triggers performs better than generic, spec-heavy bullet points.
🔹 Embrace occasion and identity Products that tie into life moments - gifting, wellness, home upgrades, parenting - are easier for COSMO to connect to shopper intent.
Final thought: TACOS is a symptom. COSMO is the shift.
If you’re throwing more spend at ads and still not seeing the organic uplift you used to - step back.
COSMO has redefined what Amazon considers “relevant”.
This is a major structural change in Amazon’s search system. The brands that win are the ones who optimise not for keywords, but for the customer’s underlying need.
If this resonates with you then get in touch with the team at ZEAL Agency - www.zealagency.co.uk - we are absolute experts in Amazon profitability and conversion rate optimisation.
