Stop Letting AI Max Bid on Every HubSpot Form Fill

AI Max changes the search problem

Google introduced AI Max for Search campaigns on May 6, 2025, and opened the beta in the Google Ads UI on May 27, 2025. By September 10, 2025, Google said the beta was available globally across Google Ads, Google Ads Editor, Search Ads 360, and the Google Ads API. That rollout matters because Search campaign expansion stopped being a keyword-only exercise. AI Max can use search term matching, landing page signals, assets, and broad match-style logic to find queries your team never wrote down.

That sounds like a targeting story. I think it is mostly a data hygiene story.

If Google can roam farther across query space, the conversion signal gets heavier. A demo request from a VP of Operations at a 280-person logistics company and a “download the checklist” form fill from a student using a Gmail address cannot carry the same weight. Yet plenty of B2B Google Ads accounts still feed Smart Bidding one primary conversion called “Lead” and then complain when AI Max finds cheap form fills.

The fix is boring in the best way. Keep tracking the early form fill, but stop treating it as the thing bidding should chase. Import cleaner HubSpot lifecycle stages into Google Ads so the algorithm learns from qualified pipeline.

What AI Max is actually expanding

AI Max is not a new campaign type. Google’s own help documentation describes it as a Search campaign feature set with search term matching, text customization, final URL expansion, locations of interest, brand settings, URL controls, and reporting changes. The part operators feel first is search term matching. Google says it uses broad match, asset-based signals, and landing page-based technology to expand reach.

In the old setup, a SaaS founder might run exact and phrase keywords around “warehouse management software demo,” “inventory planning tool,” and “3pl reporting dashboard.” With AI Max turned on, Google can match into adjacent searches if the campaign, assets, and landing pages suggest intent. Some of those searches will be gold. Some will be mush.

Google published a 14% average conversion or conversion-value lift at similar CPA or ROAS for advertisers activating AI Max in Search campaigns. For non-retail campaigns where exact and phrase keywords made up over 70% of conversions or conversion value, Google cited a 27% lift. Those numbers came from Google internal 2025 data, so I would treat them as directional, not as a forecast for your account.

Still, the direction is real. Query matching is getting looser, and Google is asking advertisers to give the system better labels.

The HubSpot mistake I keep seeing

Here is the account pattern I see in small B2B teams running HubSpot Marketing Hub Professional and Google Ads. They have one Search campaign for non-brand demand, maybe $8,000 to $35,000 a month. The main conversion action in Google Ads is a thank-you page visit or HubSpot form submission. It fires for demo requests, webinar registrations, checklist downloads, newsletter signups, partner inquiries, and the occasional vendor pitch.

Everything looks fine in week one. Cost per lead lands at $85. The founder is happy because LinkedIn was at $420. Then sales opens the leads. Half are too small, a quarter wanted the free template, and four used fake phone numbers. By the end of the month, the campaign has 116 conversions in Google Ads and 9 sales-qualified leads in HubSpot.

That gap is the whole problem.

Smart Bidding did its job against the label it was given. It found people likely to submit forms. The CRM knew which people became Marketing Qualified Lead, Sales Qualified Lead, Opportunity, and Customer, but that signal stayed trapped in HubSpot reports and Monday pipeline meetings.

HubSpot has had ads optimization events for years. The current HubSpot documentation is specific: after connecting Google Ads, you can create ad conversion events that use Google’s Enhanced Conversions for Leads to sync CRM lifecycle stage changes from HubSpot. HubSpot also notes that lifecycle-stage events only count changes after the conversion event is created. No backfill magic. Set it up before the next test starts.

Use stages as labels, not vanity milestones

HubSpot’s default lifecycle stages include Subscriber, Lead, Marketing Qualified Lead, Sales Qualified Lead, Opportunity, Customer, Evangelist, and Other. The stage names are familiar enough that teams stop questioning them. Bad idea.

For Google Ads bidding, I want stages that reflect buying intent and sales acceptance. In a typical B2B account, I would keep “Lead” visible but secondary. It belongs in reporting, not in the primary goal set for non-brand Search. The first bidding-worthy stage is usually Marketing Qualified Lead if the definition is strict: business email, target geography, company size above a floor, relevant use case, and no student or competitor domains. For many founder-led teams, Sales Qualified Lead is cleaner because it means a human accepted the record.

A concrete setup might look like this. A demo request form submission gets tracked as a Google Ads conversion action called “Form Submit – Demo Request” with a value of $25 and secondary status. HubSpot moves a contact to MQL when the form type is demo, company size is 50 or higher, country is United States, Canada, United Kingdom, or Australia, and the email domain is not Gmail, Yahoo, Outlook, or a disposable domain. That lifecycle change syncs into Google Ads as “HubSpot – MQL” with a value of $250. Sales moves the contact to SQL after a booked discovery call or a confirmed buying project, and that event syncs as “HubSpot – SQL” with a value of $900.

If the company has enough deal volume, Opportunity is even cleaner. I would rather bid on 30 Opportunities a month than 300 mixed leads if the campaigns can still learn. Volume matters, though. A $12,000 monthly Search budget with 4 Opportunities a month will usually starve tCPA bidding. In that case, use SQL as primary and keep Opportunity as secondary until volume improves.

The import mechanics are less scary than they look

Google’s Enhanced Conversions for Leads documentation says third-party imports such as HubSpot and Zapier can send user-provided data along with offline conversion events. Google recommends continuing to import GCLID when possible, and it says new enhanced conversion actions should use “Qualified lead” or “Converted lead” as the conversion goal.

HubSpot’s current Google Ads event flow lines up with that. In HubSpot, go to Marketing > Ads, create an Event, choose Google as the ad network, choose the connected ad account, and set the trigger to Lifecycle stage change. Pick the HubSpot lifecycle stage, map it to the Google lifecycle stage if needed, assign a value, decide whether the event should be a primary action in Google, and name it plainly.

Name discipline helps later. I like names such as “HS Lifecycle – MQL – Google Ads” and “HS Lifecycle – SQL – Google Ads.” Six months from now, someone will be staring at Google Ads conversion diagnostics with three browser tabs open. Cute names will waste their morning.

HubSpot’s doc has two details operators miss. First, a contact needs a Google ad click ID property, or shared contact data such as email, phone, or address. Second, if one contact moves through multiple lifecycle stages and you created events for those stages, HubSpot can sync each stage change. That is useful, but it also means you need values and primary actions set with care. Do not make Lead, MQL, SQL, Opportunity, and Customer all primary in the same Search campaign unless you want the bidding system to optimize against a blended soup.

Separate demo demand from low-intent fills

The phrase “form fill” hides too much. A demo request is a hand raise. A template download is a maybe. A newsletter signup is mostly an audience asset. A pricing-page contact form from a 500-person company running NetSuite is a different animal from a gated guide download from a personal email.

In HubSpot, I would split this with workflow logic before it reaches Google Ads. Demo request forms, contact sales forms, and pricing inquiry forms can trigger an MQL check immediately. Content forms should require extra evidence: a target-account domain, two or more high-intent page views, a return visit within 14 days, or a job title that matches the buyer group. For a SaaS company selling compliance software, “Head of Risk,” “VP Compliance,” and “General Counsel” can clear the bar. “Student,” “Consultant,” and blank title should wait.

One real operating threshold I like: do not send content-download Leads as primary conversions until the account proves a 20% Lead-to-MQL rate from that asset. If a SOC 2 checklist brings 400 leads and 18 MQLs, it can stay in remarketing and organic nurture. It does not deserve the same bid signal as “book a compliance automation demo.”

This is where paid and organic finally stop fighting. Organic can keep capturing early research demand through guides, comparisons, and templates. Paid Search can still see those assists in HubSpot attribution. Google Ads bidding, though, should get the stage that says sales would spend time on this person.

How I would test it in 30 days

Start with one non-brand Search campaign where conversion volume is real but lead quality is noisy. Turn on AI Max through an experiment if the account has the option. Google added one-click experiments for AI Max during the 2025 global beta rollout, which is exactly the kind of guardrail I want before changing the learning environment.

Before launch, clean the conversion actions. Leave form submissions as secondary. Set the best available HubSpot lifecycle event as primary: MQL if you need volume, SQL if you have enough of it, Opportunity if the sales cycle is short and the count is healthy. For a small B2B account, I want at least 30 primary conversions in 30 days before I trust target CPA changes. Below that, I watch search terms, lead notes, and pipeline manually.

Use values even if you are not ready for value-based bidding. A simple model beats flat values. If historical HubSpot data says 1 in 5 MQLs becomes SQL, 1 in 3 SQLs becomes Opportunity, and 1 in 4 Opportunities closes at $18,000 average contract value, your rough expected values are $300 for MQL, $1,500 for SQL, and $4,500 for Opportunity. The math will be imperfect. Flat $1 values are worse.

During the test, read the AI Max search terms report twice a week. Google’s AI Max reporting can show AI Max as a match type for incremental terms and includes source detail for broad match expansion or keywordless matching. I care less about whether a weird query converted and more about which HubSpot stage it produced. “inventory spreadsheet template” with 19 Leads and 0 MQLs is a negative keyword candidate. “3pl kpi dashboard software” with 2 SQLs gets its own landing page or ad group note.

The ops move is the strategy

AI Max did not remove operator judgment from Search. It moved the judgment upstream into CRM definitions, conversion values, exclusions, consent settings, and lifecycle automation.

That is uncomfortable for teams that treated Google Ads as a media-buying box and HubSpot as a reporting box. In 2026, those boxes leak into each other. Google is expanding Search through AI Max. HubSpot can send lifecycle-stage changes through Enhanced Conversions for Leads. The account that wins is the one where the CRM tells Google which demand was worth a sales rep’s calendar.

I would not wait for a perfect attribution model. Pick one clean stage, import it, make it primary for bidding, and keep every weaker form fill in secondary reporting. Then look at the search terms that produce qualified pipeline, not the queries that produce the cheapest names in the database.

That is the practical use of AI Max for Search in a HubSpot shop. Let Google explore, but make it learn from the people who actually had a shot at buying.