Bid down a bad placement instead of killing it
Bid modifiers can scale a bid, for example multiplier 0.3, on placement, site, or inventory_source. That path is seat-verified and not productized.
Published 2026-09-09 · Search job: bid modifiers vs exclusions
Bid modifiers versus exclusions is a choice between scaling a bid and removing eligibility. On this seat a bid modifier term can match placement, site, or inventory_source from a 66-key vocabulary and apply a multiplier. multiplier: 0 means do not bid. A multiplier of 0.3 would keep the placement eligible at a lower bid and keep collecting data. Hard exclude removes the inventory from targeting. We have not productized the modifier path. This page is a plan.
If you want to know which one to use on a bad placement, we can describe both levers. We cannot quote a judged flight that used 0.3 instead of a block.
Why the softer lever exists
The first real Supply Audit run found waste we then wanted to remove. Placement and site excludes work as direct keys. That is good when the placement is done. It is blunt when the sample is small. A 1,073-row zero-click list includes slots that might be unlucky, not broken. Killing them all is a one-way write. A scaled bid is reversible and still produces impressions you can read.
OPTIONS /rest/v2/bid-modifiers is the schema we trust. terms[].targeting_key is a choice of 66 keys, including placement, site, and inventory_source. Attachment is line_items.bid_modifier_id. The field exists. It is not productized in Adprime Zero.
What we will not ship from this page
We will not attach a modifier to a live campaign from a publication. We will not invent a CTR or IVT change from a 0.3 multiplier. We will not treat bid-down as a replacement for Scan then exclude. You still have to see the placement first.
Delivery modifiers are the budget-allocation sibling, not the same object. Terms there are targeting, rank, and weight, plus a required fallback_weight. The seat has had zero delivery modifier objects. That plan is Delivery modifiers as budget weights.
The exclude how-to remains Placement vs site vs domain. This file becomes an article when a dated modifier is attached, restored or left in place on purpose, and read back against the same grain.