Amazon’s Used Buy Box NIGHTMARE: What’s Happening and What It Means for Booksellers

If you sell used books on Amazon through FBA (Fulfillment by Amazon), you may have noticed something deeply unsettling in the past few weeks.

For years, the Buy Box—the section where customers can click “Buy Now”—almost always favored FBA sellers over Merchant Fulfilled (MF) sellers.

Even if an MF seller had a lower price, Prime shipping gave FBA a competitive edge.

But now? Everything seems to be changing.

Suddenly, Merchant Fulfilled sellers are winning the Buy Box at an unprecedented rate, leaving FBA sellers scrambling to figure out what’s happening.

Some have seen daily sales drop by 50-80% overnight, while others are watching MF sellers dominate—even when FBA offers are priced competitively.

What’s going on? Is this a glitch? A temporary test? Or is Amazon permanently shifting away from its FBA favoritism?

With no official word from Amazon, booksellers are left with a mix of speculation, data, and theories.

Here’s what we know so far and what it could mean for the future of selling books on Amazon.

The Buy Box Is Acting Strangely—And It’s Hitting Sellers Hard

Shannon Jakul, a part-time bookseller, had been transitioning from 100% FBA to a hybrid model before this shift happened. Looking at her numbers, she saw something alarming.

“I normally have about 1,000 items in inventory—800 FBA and 150 MF. In February, my Merchant Fulfilled books made up only 16% of my inventory and 16% of my sales. Now? That same 16% of my inventory is making up 32% of my sales. If I hadn’t started testing MF a couple of months ago, my sales would be crushed.”

For those relying solely on FBA, this change isn’t just frustrating—it’s potentially business-ending.

Many have built their entire model around sending books to Amazon, letting them handle fulfillment, and winning the Buy Box because of Prime shipping.

If that advantage disappears, some sellers could be left with warehouses full of inventory that isn’t moving.

What's Causing this Shift?

Without a clear answer from Amazon, booksellers are debating four major theories:

#1 - Amazon Is Prioritizing the Lowest Price Over Prime Eligibility

For years, an FBA seller could price higher than an MF seller and still win the Buy Box because Amazon prioritized Prime shipping. That advantage seems to be gone.

Jonathan Stuckey, an experienced bookseller, ran a test and quickly saw the pattern.

“On books with a really cheap FBM offer, the MF seller got the Buy Box. On books where FBA and FBM were priced the same, the FBA offer won. This makes me think they’ve fully switched to a price-first system.”

If this theory holds, it means Amazon’s Buy Box is now being awarded to the lowest-priced offer, regardless of fulfillment method. That’s a massive shift.

It forces sellers into aggressive price wars, which could crush profit margins.

Some sellers, however, aren’t convinced it’s just about price.

If it were that simple, why are some MF sellers winning even when they are priced higher than FBA?

That suggests other factors may be influencing Buy Box placement, such as seller performance metrics, condition notes, or even Amazon testing a new algorithm.

#2 - Amazon Is Pushing Sellers Toward Merchant Fulfilled

Another theory is that Amazon is deliberately encouraging sellers to move away from FBA.

Why? Because FBA is expensive—for Amazon.

By shifting more sales to Merchant Fulfilled sellers, Amazon:

Reduces warehouse congestion (books take up a ton of space).
Lowers fulfillment costs (Amazon no longer has to handle packing and shipping).
Minimizes liability (lost or damaged books become the seller’s responsibility, not Amazon’s).

Michael Krider, a seller analyzing Amazon’s API, noticed something strange in the backend data.

“The SP-API code still returns data showing that FBA books are winning the Buy Box, but that’s not reflected on the product detail page. It’s like Amazon’s own system doesn’t match up with what buyers are seeing.”

If Amazon were testing a shift toward MF, it wouldn’t be the first time.

They’ve made sudden changes before—without warning sellers.

But there’s a problem with this theory: If Amazon was trying to push more sellers toward MF, wouldn’t they have communicated that by now?

#3 - A Glitch or Algorithm Test Gone Wrong?

Some sellers believe this might just be a temporary bug or an algorithm update that didn’t work as expected.

Chad Coleman, a long-time seller, thinks the change doesn’t add up.

“Amazon is rewarding the cheapest MF offer in the best condition. That doesn’t make sense—it incentivizes sellers to ‘overgrade’ books, which could lead to more returns and refunds. The Buy Box never used to discriminate by condition, at least for books. My guess? This is broken and needs to be fixed.”

If this is just a glitch, Amazon might correct it soon—restoring Buy Box favoritism to FBA sellers.

But if that were the case, why hasn’t Amazon fixed it yet?

The change has persisted for weeks now, and Amazon has been known to roll out tests without notifying sellers.

#4 - Legal Pressure & Antitrust Concerns

A fourth theory suggests that Amazon’s Buy Box changes are being driven by legal pressure.

On March 7, 2025, Amazon was in court defending its Buy Box policies.

The lawsuit argued that Amazon’s previous Buy Box system was anti-competitive because it forced sellers into FBA by giving Prime sellers an unfair advantage.

Daniel Mull, referencing the case, noted:

"It's not a glitch nor is it permanent. They are literally arguing with the FTC about this in court and presenting evidence to the judge for what a world without the Buy Box would look like. These are their words, not mine."

"The Federal Trade Commission told a Washington federal judge Friday that it can only offer pieces, and not the entire outline, of what an alternative world might look like without Amazon's allegedly monopolistic pricing floor."

"Enforcers accuse Amazon of artificially inflating online retail prices by conditioning 'Prime' eligibility on using its expensive fulfillment service."

The lawsuit accuses Amazon of using its Prime eligibility as a way to control the marketplace, forcing sellers to use FBA or risk losing sales.

If this theory is true, it could mean this change is permanent. Amazon might have removed FBA favoritism to protect itself legally.

But then again, Amazon has fought legal battles before without making drastic changes to its Buy Box system.

If they were truly trying to comply with regulators, wouldn’t they have issued a public statement?

What Should Sellers Do Now?

With so much uncertainty, sellers are being forced to rethink their entire approach to selling used books on Amazon. Many are making major adjustments—and fast.

Some are shifting to Merchant Fulfilled (MF) for the first time, hoping to win back the Buy Box.

Others are experimenting with different pricing and condition strategies to see if they can regain visibility.

The reality is, the sellers who adapt the quickest will be the ones who survive this shift.

Here are some proven strategies sellers are using right now—backed by real data and experiences from the community.

1. Test Merchant Fulfilled Listings

If you’re an FBA-only seller and your sales have dropped, now is the time to start testing MF.

Shannon Jakul was already in the process of transitioning to a hybrid model before this change, and the results have been clear:

“I normally have about 1,000 items in inventory—800 FBA and 150 MF. In February, my MF inventory accounted for only 16% of my sales. Now, that same 16% of my inventory is making up 32% of my total sales. If I hadn’t started testing MF a couple of months ago, my sales would be crushed.”

Many booksellers are finding that simply duplicating their FBA listings as Merchant Fulfilled is allowing them to regain some control.

If Amazon is currently favoring MF, having both options in your inventory ensures you aren’t losing out.

Action Steps:

Start by listing 10-20% of your slower-moving inventory as Merchant Fulfilled.
Keep shipping supplies (mailers, labels, scales) ready to handle MF orders efficiently.
Offer fast shipping times to remain competitive—Amazon’s algorithm may favor quicker MF orders.

2. Adjust Your Pricing and Repricing Strategy

Many sellers believe that repricers are making the problem worse by constantly undercutting prices, which may be accelerating price drops across the board.

Nic Sosa, a bookseller, is reconsidering how often he adjusts prices:

“I don’t have my repricer chasing the Buy Box. I only make price changes a couple of times a week. I’m beginning to think that changing the price every couple of hours to every couple of minutes does not give a reliable price point to the Amazon price analysis system.”

Some sellers are now avoiding automated repricers altogether and instead adjusting prices manually based on Keepa data and historical trends.

Action Steps:

Stop racing to the bottom. If MF sellers are winning on price, undercutting further may not help.
Use Keepa to study past price trends and price accordingly.
If your book is historically stable at $40-$50 but is now at $25, it may be best to hold firm rather than panic-sell.
Consider raising prices slightly on FBA listings to see if the Buy Box algorithm shifts back in favor of Prime offers.

3. Experiment with Condition Notes & Listings

There is growing speculation that condition might now play a bigger role in Buy Box placement.

Historically, many booksellers defaulted to listing everything as ‘Good’ to save time. But if Amazon is now prioritizing ‘Like New’ or ‘Very Good’ listings, then adjusting your condition strategy could help win the Buy Box more often.

Michael Krider, after investigating Amazon’s backend data, believes something is off with how the Buy Box is being assigned:

“The SP-API code still returns data showing that FBA books are winning the Buy Box, but that’s not reflected on the product detail page. It’s like Amazon’s own system doesn’t match up with what buyers are seeing.”

Some sellers believe that books marked as ‘Like New’ may be gaining an advantage. If Amazon has shifted its algorithm, better-condition listings could be given more weight than before.

Action Steps:

If a book is in excellent condition, consider listing it as ‘Like New’ or ‘Very Good’ instead of defaulting to ‘Good.’
Avoid overgrading—customers may return items if they feel misled.
Watch Keepa data to see if higher-condition listings are selling faster.

4. Leverage Data Tracking Tools Like Keepa

Booksellers who have relied only on scanning apps like Scoutly or ScoutIQ are realizing that they may not be getting the full picture of an item’s true value.

Joji Davenport emphasized the importance of analyzing historical pricing:

“If the changes to the FBA Buy Box are killing your business right now, my #1 piece of advice is that you need to invest time in learning how to properly value books by watching some Keepa tutorials. The booksellers in trouble right now are people sending in books with no value and an inflated Buy Box. Exploiting the Prime gap works when there is one, but it doesn’t when it vanishes.”

Action Steps:

Use Keepa to look at the last 90-180 days of sales data instead of relying solely on live scans.
Avoid books that only recently spiked in price but have no long-term sales history.
Watch for seasonal price trends (e.g., textbooks often spike at certain times of the year).

5. Diversify Beyond Amazon (If Necessary)

Some sellers are taking this as a wake-up call to reduce their dependence on Amazon.

For years, booksellers have relied on FBA’s dominance to drive sales. But with Amazon making unpredictable changes, sellers are starting to explore other selling platforms.

Geo Smith, a seller adapting to the changes, pointed out:

“Those who don’t find ways or create new strategies will inevitably get left behind. Some Amazon book sellers who haven’t given up are probably happy because they now have fewer competitors since others have backed out or quit.”

Action Steps:

Cross-list high-value books on platforms like eBay, Facebook Marketplace, and Biblio.
Build an email list or website for direct sales to book collectors. (very hard to do)
Test wholesale or bulk book sales to libraries or local businesses.

Is This the New Normal?

No one knows for certain if Amazon will reverse this change, make additional adjustments, or leave things as they are.

It could be a temporary algorithm test that will be corrected in a few weeks, or it could be part of a broader strategy shift where FBA is no longer prioritized the way it once was.

Some sellers believe Amazon is simply testing how the marketplace responds.

Others think legal pressures are forcing Amazon to level the playing field between FBA and MF sellers.