What is Dynamic Bids Down Only?
Dynamic Bidding, Down Only
An Amazon bidding strategy in which Amazon may lower your bid in real time for unlikely conversions, but never raises it.
Dynamic bids, down only is one of three Sponsored Products bidding strategies. Amazon may reduce your bid in real time when it judges a click less likely to convert, and it never bids above the figure you set.
What that gives you
Your bid becomes a ceiling. Whatever an auction costs, it will not cost more than the bid you entered multiplied by any placement modifier in play. That single property is why it is the safest strategy to run while you are still learning what a campaign is worth.
The protection matters most where match types are loose. Auto campaigns, broad match and phrase match all reach queries you did not choose, and down only reduces exposure to the weakest of them without you having to catch each one by hand.
What it costs you
You cannot capture an auction that is worth more than your bid. When Amazon predicts an unusually strong click, down only will not reach for it. On a keyword you have already proven, that restraint is real money left on the table.
The measurement benefit
Under down only your realised cost per click sits at or below your bid, once any placement modifier is accounted for. That keeps the relationship between the setting and the outcome interpretable, which matters because every bid calculation worth doing is anchored on cost per click rather than on the bid.
RPC = Sales ÷ Clicks
Target CPC = RPC × Target ACOS
If your reported cost per click sits well below your bid under down only, Amazon is discounting a large share of your auctions, which is itself a signal about the quality of the traffic that keyword reaches.
The house default
Shurq's doctrine pairs fixed bids with dynamic down only, and puts the shaping work into placement modifiers and hourly schedules rather than into asking Amazon to guess. The reasoning is that a modifier is a lever you can measure and reverse, while a real time adjustment is neither. Down only is the sensible protective setting for discovery campaigns and for anything not yet understood.
Choosing between the three
| Strategy | Amazon may lower | Amazon may raise | Best used for |
|---|---|---|---|
| Down only | Yes | No | New campaigns, auto, broad, phrase |
| Up and down | Yes | Yes | Proven keywords with margin headroom |
| Fixed | No | No | Clean tests and tight control of the auction price |
Whichever you pick, hold it steady within a campaign for long enough to read the result. Attribution settles late, so an early verdict on a bidding change tends to be unfair in one direction or the other.
Examples
- →Running a new auto campaign on down only while search terms are still being reviewed.
- →Reading a realised cost per click far below the bid as a signal of weak query quality.
- →Pairing down only with placement modifiers rather than asking Amazon to raise bids.
Related Terms
Dynamic Bids Up and Down
An Amazon bidding strategy in which Amazon may raise or lower your bid in real time based on conversion likelihood.
Fixed Bids
An Amazon bidding strategy in which your bid is used exactly as set, with no real-time adjustment by Amazon.
Bid Adjustment
Any change applied to a base bid, by the seller, by a placement modifier, or by Amazon's dynamic bidding at auction time.
CPC
Cost Per Click - the amount you pay each time someone clicks your ad.
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