Amazon isn’t showing you the best prices unless you are a Prime member or placing a large order

Amazon has been going to increasingly great lengths to convert shoppers into Prime members and merchants into sellers whose products are eligible for Prime’s speedy delivery service.

But a new report from the nonprofit investigative news organization ProPublica shows Amazon may have crossed a line.

The report, published on Tuesday morning, found problems with Amazon’s price-comparison pages, which are supposed to allow customers to find the lowest price on a given product. But the tool seems to rank products in a way that favors items sold by Amazon, or merchants who pay Amazon to ship products on their behalf.

When Amazon sorts products by price on a page like this, it includes the cost of shipping fees in its calculation for some products, but not for others.

Specifically, products sold by third-party merchants not participating in Amazon’s shipping service are ranked according to the product’s price plus the shipping fee.

But products sold by Amazon or from third-party merchants that participate in its shipping service are ranked without the shipping cost added, thus showing them as cheaper than they really are.

Part of the reason for that discrepancy may be that Amazon Prime members generally do not pay for shipping, and so for those customers, the price comparison rankings would be accurate. Some non-Prime members also make sure they spend $49 on an order, so that it hits the threshold for free shipping. The price-comparison lists would be accurate for those customers as well.

But for the average customers who do not pay Amazon $99 a year to participate in the Prime program — and don’t plan to spend $49 on an order — the prices they see on these lists do not reflect the final cost. In these cases, Amazon products may be shown as cheaper when the cost may be higher depending on the shipping fee.

We’ve reached out to Amazon for comment and we’ll update if we hear back.

Update: Amazon responded with the following comment:

With Prime and Super Saver Shipping (which requires no membership and ships orders above $49 for free), the vast majority of our items — 9 out of 10 — can ship for free. The sorting algorithms the article refers to are designed for that 90% of items, where shipping costs do not apply.

To be clear, while nine out of 10 items can ship for free, as Amazon states, it’s sometimes contingent on the order totaling $49 or more. Costumers don’t necessarily see the shipping cost for items when ordered below the $49 threshold and these items might rank differently when factoring in the shipping cost.

Update No. 2: Amazon is now saying the first statement wasn’t completely accurate so they’ve requested an update. The new statement looks a lot like the above excepted the word “items” has been changed to “items ordered” in both the first and second sentence. The new statement still doesn’t address the fact that if a non-Prime member looks at a price comparison page, they are seeing inaccurate rankings unless they plan on hitting the $49 free-shipping threshold.

With Prime and Super Saver Shipping (which requires no membership and ships orders above $49 for free), the vast majority of our items ordered – 9 out of 10 – can ship for free. The sorting algorithms the article refers to are designed for that 90% of items ordered, where shipping costs do not apply.

This article originally appeared on Recode.net.

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