Just a few hours into the 2026 Prime Day, the seller group has already gone crazy. Some sellers have seen their order volume triple, some have ACOS so low it's unbelievable, and others have backend data that's all red, but they're getting more and more anxious.

We've pulled real-time data from top and mid-tier sellers across multiple categories and found three signals that almost simultaneously emerged. Together, they point to a truth that all Amazon sellers must face: The explosive orders you see may be systematically devouring your profits.

Below, we'll break down the hidden risks under this carnival from these three topics one by one.

1. Behind the ROAS Surge, There's a Structural Problem

On the morning of the first day of Prime Day, the ROAS of several advertising campaigns reached recent peaks. A seller in the home goods category told us that their usual ROAS of around 3.5 for targeted advertising shot up to 8.2 this morning, with an absurdly high order conversion rate.

Many people would subconsciously think: Isn't this the dividend of a big promotion? High-quality traffic, strong user purchasing willingness, of course, the advertising efficiency is high.

But when you look at the data in detail, the problem arises.

We found that for these high ROAS advertising campaigns,over 60% of the transactions were concentrated on a few main ASINs, and these ASINs all have one thing in common—they are hot-selling links with a large amount of inventory prepared in advance, and they offer the biggest price discounts. At the same time, the advertising clicks and conversions for mid-tier products and long-tail variants within the same store have significantly declined, and some SKUs have lower click-through rates and CVR (conversion rates) than usual even with the influx of promotional traffic.

What does this mean? It means that the so-called "ROAS surge" is not an improvement in overall advertising efficiency, but rathertraffic is being concentrated by the head links with large discounts and high inventory, forming a Matthew effect. During Prime Day, the platform's algorithm will prioritize allocating traffic to the links that can best catch and are most likely to close the deal, and the heavily discounted hot-selling items just happen to meet this condition.

The consequences of this structural problem are very concealed. On the surface, advertising spending is worthwhile, but in reality,the product matrix of the store has not "upgraded" along with it, but has become further top-heavy. Once Prime Day is over and the hot-selling items return to their original prices, traffic will plummet, and the mid-tier products have not accumulated enough weight with the help of the promotion, the traffic structure of the entire store will show a clear fault.

What's more frightening is that many operators will be paralyzed by the short-term high ROAS and continue to add budgets to the head links in the following days, or even blindly expand keywords and raise bids, completely ignoring the traffic feeding of the store's core ASINs. When the promotion is over and the high ROAS recedes like a tide, what remains is an overly concentrated traffic structure and a more fragile product ladder.

The high ROAS of Prime Day is often not a victory of advertising ability, but an extreme tilt of the traffic allocation mechanism towards heavily discounted head links. If you can't see this layer, the joy of explosive orders will soon turn into a long pain after the promotion.

2. The Goods Are Gone, But the Advertising Is Still Burning

If the first problem is a structural chronic disease, then the second problem is direct bleeding.

We pulled data on a batch of ASINs that were out of stock and found a startling phenomenon:During the Prime Day flash sale/coupon effective period, after some SKUs sold out, the corresponding advertising campaigns did not pause in time, continuing to consume the budget for an average of 2.7 hours. Some sellers, because they manage multiple sites and activities at the same time, even had their goods out of stock for half a day, and the advertising was still burning.

You know, during Prime Day, advertising bids are generally 30%-50% higher than usual, or even higher. This means that during those hours when the goods were out of stock, every click was eating away profits in vain, and it was expensive clicks. The backend seems to show that the order volume is still rising and the conversion rate is online, but the actual traffic has no inventory to receive, directly jumping to the "Currently unavailable" page, which not only gives a poor user experience but also wastes advertising expenses.

Why does this happen? There are three reasons:

• First,there is a serious "information lag" between inventory management and the advertising backend. The outbreak of Prime Day orders is often pulse-like, the countdown bar runs fast, the system inventory data update lags, and by the time the backend shows a shortage, it has actually been more than ten minutes or even longer. And most sellers can't manually monitor every minute in real-time.

• Second,the superposition of multiple activities leads to rule confusion. This year, many sellers signed up for Prime exclusive discounts, coupons, and promotional activities at the same time, and the inventory allocation logic is more complicated than in previous years. Some links sold out under a certain sub-activity, but other related advertising groups did not stop in conjunction and were still running.

• Third,the psychology of "fear of losing weight". Some operators know that they are about to run out of stock, but they dare not easily pause advertising, fearing that once the advertising weight drops, they will not be able to grab it back after the promotion ends. This hesitation directly causes the waste of real money under the high-speed rhythm of Prime Day.

We used a set of simulated data to calculate this account: For a product with a unit price of $29.99, assuming a CPC of $2.5 during Prime Day, if the advertising continues for 3 hours after the stock runs out, and 200 clicks occur during this period, then it directly burns $500. And the entire profit of this SKU on the day of the stock-out may be just over $2,000. This means thatone-quarter to one-fifth of the profit was eaten by ineffective advertising after the stock ran out.

What's more heartbreaking is that these clicks did not generate any transactions, but the advertising data is still rising, and ACOS exploded the next day, and you still have to spend time reviewing which link went wrong.

3. AI Shopping Makes the Cost of Stock-Outs Higher

If "the goods are gone but the advertising is still burning" is visible bleeding, then the third problem is more concealed but may cause long-term damage to the store.

In the 2026 Prime Day, an undeniable variable isthe large-scale intervention of AI shopping assistants. Rufus and Amazon's in-site AI search and recommendation capabilities are no longer just "auxiliary functions," but have truly become the shopping entrance for a large number of consumers. More and more users will directly use AI dialogue to find Prime Day deals, compare products, and get recommendations.

What does this mean? It means that the user's shopping path has shortened, the decision-making speed has increased, and at the same time,the real-time perception of inventory status has also strengthened.

In the past, a consumer would search for keywords, scroll through lists, click into product pages, and find that they were out of stock, they might search again or browse the store for substitutes. But now, the logic of AI shopping assistants is: once a product is out of stock in its recommended options, it will immediately direct traffic to the next best choice—and this "best choice" is very likely to be your direct competitor.

We observed a typical case: A Bluetooth headset seller's main model ran out of stock around 10 am on Prime Day, but the keyword ranking and search exposure of the product remained high. Many users asked the AI assistant "the most worthwhile sports headset to buy on Prime Day", and the system was still recommending this out-of-stock headset. After clicking in and finding it unavailable, the AI would immediately recommend similar products with similar functions and close ratings, and these competitors often had Prime Day discount tags.

From stock-out to competitor interception, the whole process may take no more than 10 seconds.

What's more frightening is that AI's recommendation weight will be retrained in this interaction. Once the feedback of stock-out appears frequently, Amazon's model may dynamically lower the recommendation priority of the product or even the store in the subsequent recommendations. That is to say,a stock-out loses not only the direct sales during the stock-out period but also the "hidden weight" in the AI recommendation system. This loss is difficult to quantify, but the impact may last for several weeks.

For sellers, this poses a new requirement: the inventory safety margin must be higher than in previous years, and the replenishment rhythm must be more accurate. In the past, you could rely on the long-tail effect of natural search to ease things down, but now AI compresses the shopping decision into a few minutes. Once you drop the chain, the business is immediately taken over.

Additionally, in the AI shopping scenario, users' tolerance for "out of stock" is also rapidly declining. Because they have become accustomed to being quickly satisfied, seeing "not available" the first reaction is not to wait, but to turn to the next recommendation. This means that the customer churn rate caused by stock-outs has been further amplified in the 2026 Prime Day.

In conclusion

Prime Day has never been just a feast of explosive orders; it is also a mirror that exposes the structural flaws hidden in the store under high traffic and high rhythm pressure.

When ROAS surges, you need to see clearly who is receiving the traffic and whether the product ladder is growing synchronously; when the goods are out and the advertising is still burning, it tests the team's execution speed and respect for the rules; in the era of AI shopping, the cost of stock-outs is no longer simply selling dozens of units less, but the traffic is redistributed by algorithms, and the weight is silently diluted.

Prime Day has just started this year, and it's not too late to correct now. It is recommended that all sellers do three things immediately: First, keep a close eye on the inventory consumption speed of the main SKU, set up real-time alerts, and decisively pause related advertising once the red line is touched; Second, check all ongoing advertising campaigns to ensure that no advertising is paying for out-of-stock links; Third, reassess the exposure opportunities of long-tail products and mid-tier ASINs, don't bet all traffic on head hot-selling items, and leave yourself a way out after the promotion.

The fiercer the traffic, the more sober you must be. The real winner is never the one who sells the craziest, but the one whose store can continue to move up after selling.