Price swing alert: how much price movement should hold an eBay listing for review?

What is a price swing alert?

A price swing alert is a check in a repricing system that notices when a supplier's price has moved unusually far, unusually fast, and holds the matching eBay price change until someone has looked at it. Instead of pushing the new price straight to eBay, the system keeps the current price, flags the listing and waits for a decision.

It exists because most bad prices start as a bad reading or a short-lived spike. A cost that doubles overnight might be a real increase. It might also be a different seller taking the buy box, a used offer being read as new, a price in the wrong currency, or a short promotion ending. Each of those would push a wrong price onto your eBay listing if nothing stopped it.

A swing alert is one part of a wider price circuit breaker, alongside a floor and a ceiling. Our guide to the price circuit breaker covers how the three work together. This article is about one question: how big a move should trigger a hold?

Why not let every price change through?

Automatic repricing saves time precisely because it does not ask you about every change. Most changes are small and genuine, and they should go through. The trouble is the rare large change that is wrong.

• A wrong drop can sell stock at a loss. If a misread puts your cost at half its real level, your eBay price falls and buyers rush in.
• A wrong rise loses sales and search position. If a temporary spike doubles your price, the listing stops selling until the spike passes.
• A real but sudden move may still deserve a look, for example when a product is about to go out of stock and only expensive sellers remain.

Our guide to spotting an Amazon price error or misread lists the common causes of a wrong reading. A swing alert is how you catch them before they reach eBay.

How big a move should trigger the alert?

There is no single right threshold, but there are good principles. A threshold that is too tight floods you with holds you wave through without reading. One that is too loose lets real errors through.

Use a percentage and a cash amount together

A pure percentage misbehaves at both ends of the price range. A 20% move on a £3 item is 60p and probably harmless. A 20% move on a £300 item is £60 and worth a look. Setting both a percentage and a minimum cash amount, and holding only when both are passed, keeps cheap items from generating noise.

Treat drops and rises differently

A drop in cost leads to a lower eBay price, and a wrong low price can lose money on every sale. A rise leads to a higher price, and a wrong high price mostly costs sales. Many sellers set a tighter threshold for drops than for rises for that reason.

Set thresholds by price band

The table below is an example of a starting point, with hypothetical numbers. Adjust it from your own hold history after a few weeks.

What should the move be measured against?

A swing is only meaningful against a stable reference. Three common choices:

• The last confirmed price. Simple, but if the last price was itself a short low, the next normal reading looks like a jump.
• A recent average. Smooths out noise, but reacts slowly to a genuine change.
• The recent high. Pricing from the highest cost in a short recent window protects margin when a supplier price is bouncing up and down, at the cost of a slightly higher eBay price for that period.

For volatile products the third option is often the most practical: if the cost has swung within the last day, price from the top of that range until it settles. For steady products the last confirmed price is fine.

What should happen when a listing is held?

A hold must have a clear default, or held listings sit in a queue doing the wrong thing.

1. Keep the current eBay price while the hold waits, unless the new cost is above it, in which case you may be selling at a loss.
2. Set the quantity to 0 if the new cost would make the current price lose money. Better to pause sales than sell at a loss while you check.
3. Read the supplier page again after a short interval. If the second reading matches the first, the move is probably real.
4. Check the cause: seller, condition, currency, delivery charge and delivery date. A different seller in the buy box explains many swings.
5. Release or reject with a note of the reason, so the same cause is recognised next time.

If you source from Amazon or another retailer, keep the rules in view: eBay's drop shipping policy allows dropshipping from a wholesale supplier, but listing an item and then buying it from another retailer or marketplace that ships directly to your buyer is not allowed. Whatever your supply, you are responsible for delivery within your stated time and for the buyer's satisfaction.

A worked example

Example, with hypothetical numbers: suppose a pair of headphones has a confirmed supplier cost of £42 and sells on eBay at £59.99. On Tuesday morning the reading shows £24.

1. The drop is £18, or about 43%. The £10 to £50 band holds drops above 20% and at least £3, so the change is held and the eBay price stays at £59.99.
2. A second reading twenty minutes later shows £24 again, from a different seller, condition 'used'.
3. The reviewer rejects the change: the new price is for a used item and the listing is new.
4. On Wednesday the reading shows £46, from the original seller, new. That is a rise of about 10%, below the rise threshold, so it goes straight through and the eBay price rises to cover the new cost.

Without the alert, Tuesday's misread would have cut the eBay price far below cost, and any sale at that price would have lost money.

Which listings need a tighter price swing alert?

Some listings deserve closer watching than the band table suggests. Tighten the alert, or review every large move by hand, for:

• Best sellers. A wrong low price on a listing that sells several times a day can lose money many times before you notice.
• Listings with large stock or no stock limit. If eBay shows a high quantity, a bad price can sell repeatedly.
• Products with several sellers on the source page. The cheapest offer changes hands often, and the condition or delivery time may change with it.
• Products around sale events. Prices often move sharply at the start and end of big promotions, and the move back can be as sudden as the move down. Our guide to how often Amazon prices change covers the patterns to expect.

Listings that sell rarely and have steady costs can use looser alerts, because the cost of a missed error is small and the cost of reviewing every hold is your time.

How do you tune the threshold over time?

Look at your holds once a week for the first month, then monthly.

• If you release nearly every hold without changes, the threshold is too tight for that band. Loosen it.
• If a bad price got through, find the band it was in and tighten it.
• If one product triggers holds every day, it is volatile. Price it from a recent high, or consider whether it is worth selling.
• If holds pile up unread, you have too many. A swing alert only works if someone acts on it.

Repricing tools handle this differently, so check how yours does it. Dropizon, for example, includes an optional swing limit in its price circuit breaker, and holds wait for one-click review with the reason recorded. Whatever you use, make sure you can see why each listing was held and what the reading was.

A quick checklist

1. Set swing thresholds as both a percentage and a cash amount.
2. Use tighter thresholds for drops than for rises.
3. Set different thresholds for different price bands.
4. Decide what a held listing does: keep its price, or go to quantity 0 if it would lose money.
5. Confirm a big move with a second reading before releasing it.
6. Review your hold history and adjust the bands every month.