Lore

Broad Match Modifier (Undocumented Fourth Match Type)

Amazon documents three keyword match types — exact, phrase, and broad (see Keyword Match Types (Exact / Broad / Phrase)) — but a fourth, undocumented match type exists: the broad match modifier. It's accessed by selecting broad match in Seller Central and prefixing required words with a plus sign (e.g., "+phone holder").

Mechanism

Any word marked with a + prefix is forced to appear somewhere in the customer's search term (in any order, not necessarily adjacent to other required words), while unmarked words remain fully flexible for Amazon to substitute or drop — the same substitution latitude ordinary broad match has.

Use case

The modifier's main value is forcing inclusion of a known audience/avatar term that Amazon has no way of independently inferring as relevant — e.g., forcing "mom" or "women" into a "+mom phone holder" target so the ad only shows for that audience segment, while still letting Amazon substitute "holder" for "stand" or similar.

Why it matters

Described as becoming the most important match type fairly quickly as Amazon's ranking/targeting systems lean further into AI-based placement (see the AI-targeting note in Keyword Match Types (Exact / Broad / Phrase)) — it's the one lever that keeps broad match's algorithmic flexibility while still guaranteeing an advertiser-chosen term isn't dropped.

Supersedes Most of Phrase Match

Supersedes Most of Phrase Match

Broad match modifier (+word) functionally replaces most of phrase match's use case: it can guarantee a required word's inclusion (e.g. +mom) while still letting Amazon substitute or reorder the rest of the search term — phrase match preserves word order but can't selectively force just one word. One PPC agency managing a portfolio of brands doing over $6M/month in revenue reports using all four match types (exact, phrase, broad, and broad match modifier) rather than dropping phrase match entirely, so the two aren't fully interchangeable in practice. See Keyword Match Types (Exact / Broad / Phrase).