What Is Modified Broad Match In Google Ads

If you recently took over a Google Ads account or find yourself auditing a Google Ads account then you might have seen something in the keywords that you haven’t seen before. You might see a plus sign before or in the middle of a keyword string.

It is completely wild that you are seeing this, but you are not crazy.

Coming across a Broad Match Modifier (BMM) keyword the one with the + sign in a live account today feels like uncovering a fossil. But I saw it in 2 accounts this week so I take it as a sign from the universe that I should address it head on.

Google officially began phasing out Broad Match Modifier way back in 2021, meaning no one has been able to create a new broad match modified keyword for half a decade. Yet, legacy accounts that haven't been touched or cleaned up in years still have them floating around.

When you run into this during an audit or when taking over an account, it can completely trip you up if you don't know how Google treats them today. Here is a breakdown of what is actually happening under the hood and exactly how to handle it without destroying your historical data in the Google Ads Account.

What Was Modified Broad Match, Anyway?

Before its sunset, Modified Broad Match (+keyword) was the beloved "sweet spot" for search marketers. It was a bridge between the chaos of standard Broad Match and the strictness of Phrase Match.

By placing a plus sign in front of a word (e.g., +men's +shoes), you told Google: "I don't care what order the user types this in, and I don't care what other words they add, but the words 'men's' and 'shoes' must be in the search query." It gave us great reach without matching for wild, irrelevant synonyms.

WE LOVED THIS MATCH TYPE.

Why It Is No Longer Relevant (And How It Acts Now)

When Google Ads sunset BMM, they didn't automatically delete your old keywords. Instead, they changed how the backend interprets them.

Officially, Google rolled BMM's behavior into an "updated" Phrase Match. However, as the platform has leaned aggressively into AI-driven, intent-based matching, any legacy BMM keyword left in an account today effectively functions with the expansive reach of Broad Match.

Because the old guardrails of the + sign are entirely ignored by modern algorithms, keeping them in your account means you are targeting queries based on loose semantic relevance, not strict keyword inclusion.

The Golden Rule: Do NOT Delete the Keyword

Your instinct when seeing an old BMM keyword might be to hit "Delete" or "Pause" immediately and replace it. Don't do that yet.

Sadly that legacy keyword is holding all of your historical data.

In Google Ads, data is equity.

That specific keyword record contains years of conversion history, Quality Score data, and algorithmic learning that your Smart Bidding strategies (like Target CPA or Target ROAS) are actively using to find customers. If you delete it, that history is gone, and your bidding algorithm goes into a bit of a shock.

Step-by-Step: The Clean, Data-Safe Playbook

To get rid of the eyesore without losing your historical data momentum, you have to execute a "gradual passing of the torch."

Step 1: Leave the legacy BMM running: Do not touch it yet.

Keep the +keyword active for now. Acknowledge that it is currently functioning with broad reach, and keep a very close eye on your Search Terms Report to add negative keywords for any junk traffic it pulls in.

Step 2: Introduce the modern Broad Match keyword: Same ad group.

Add the exact same keyword into the ad group as a true Broad Match (plain text, no symbols). Because the algorithm is already treating the old BMM as a broad match, this mirrors the intent safely.

Step 3: Wait for data collection: Can take weeks to months.

Let both keywords run simultaneously. Google will naturally begin shifting impressions over to the new, clean Broad Match keyword as it builds its own historical profile. Wait until the new keyword pulls in steady impressions and matches (or beats) the conversion performance of the old one.

Step 4. Pause the legacy keyword match type :The final cleanup.

Once the new Broad Match keyword has safely inherited the data footprint and is running efficiently, go ahead and Pause (never Delete) the old +keyword. Your account is now clean, and your data remains intact.

An Alternative Option: If you are auditing an account and realize that a true Broad Match is expanding too wildly for the budget, you can introduce the modern Phrase Match ("keyword") in Step 2 instead. This will tighten the targeting back up to look closer to how BMM used to feel years ago.

Finding these in an account is the ultimate diagnostic proof that an account has been neglected.

By handling it patiently, you keep the algorithm happy while bringing the account architecture into the modern era.

Wrap Up

Finding a Broad Match Modifier keyword in 2026 feels like opening a time capsule — but it’s also one of the clearest signs that an account has been running on autopilot for years. And that’s exactly why you can’t treat it like a simple cleanup task.

The instinct to “fix it fast” is what gets most advertisers into trouble.

The real work is understanding how Google interprets legacy data, how Smart Bidding leans on historical signals, and how modern intent matching behaves under the hood.

That’s the difference between a protective approach and a reckless one.

So when you stumble across a +keyword in the wild, don’t panic and don’t delete.

Treat it slowly, knowing it’s holding years of algorithmic learning. Let the new keyword inherit the equity. Keep the machine stable while you modernize the structure.

Because this is the part no one tells you and not ChatGPT or AI:

Old match types aren’t dangerous — deleting their data footprint is.

Handle them with patience, precision, and respect for the history baked into the account. That’s how you protect performance while bringing the architecture into the current era of AI‑driven matching.

If you want to go deeper into how Google interprets intent today, you can explore modern broad match behavior or learn how to build AI‑safe keyword structures that won’t collapse under automation.

You’re not just cleaning up an account. You’re restoring it — and giving it a future the algorithm can actually understand.