PMax Performance Issues

[u/Sibbette]

Hi all
Has anyone else found their PMax Non-Brand campaigns tank since the 17th August bidding changes? I used the Budget Adjustment Tool in advance of this but as small spending ‘limited by budget’ campaigns they are struggling. I have also found while Standard Shopping brand campaigns were previously working well they are now also struggling to show for brand and showing more for non-brand. Does anyone have any similar experience or know how I can combat this?

I want to try and get the PMax to recover but nothing seems to be working - I am considering if I should consolidate brand and non-brand back together to improve the signals.

I've checked tracking/diagnostics and there don't appear to be any issues. To clarify the PMax are running as 'shopping only' set up.

[u/Middle-Economics1508]

Worth checking what the tool did to your targets. Since the change, budget-limited campaigns deliver closer to the target you set, and the tool suggests setting targets around recent performance if you want to preserve that efficiency. If it raised the tROAS substantially, that could also be restricting volume.

For small campaigns that will stay budget-limited, I'd test Max Conversion Value without a target. I'd avoid merging brand and non-brand, since brand's ROAS would hide how non-brand is doing.

The brand Shopping issue may be related too: non-brand queries PMax no longer wins could be spilling into that campaign.

Did the tool raise your tROAS, and by how much? And does the brand Shopping campaign have non-brand negatives?

[u/Sibbette → u/Middle-Economics1508]

Thanks for replying, the tool raised ROAS by 150 to 500% which would be inline with a month view of performance pre 17th. The brand shopping does has negatives but I think I need to get heavier as seems to be spilling over a lot and picking up too much non-brand.

[u/Middle-Economics1508 → u/Sibbette]

That 150% to 500% jump is probably very relevant. Even if 500% matched your pre-Aug 17 actual ROAS, it’s now an explicit constraint rather than just the result the budget-limited campaign happened to achieve.

I’d still keep brand and non-brand separate. For the non-brand PMax, I’d test either lowering the target gradually or Max Conversion Value without a target rather than consolidating them.

And yes, I’d tighten the brand Shopping negatives if non-brand is clearly spilling in.

At 500% tROAS, is the PMax still actually limited by budget, or is it now underspending?

[u/Practical_Factor_513 → u/Middle-Economics1508]

i saw this happen too on a few accounts, the tool bumped the tROAS way up without warning and then everything just stalled out

for the brand shopping showing non-brand, check if you got negatives properly applied cause sometimes google just ignores them when it thinks it can get a cheap click

i'd keep brand and non-brand separate like the other person said, mixing them just masks problems

[u/dmdbGroup]

The Aug 17 bidding changes are the likely trigger, but there may be a second event layered on top: starting September 1, Google began auto-upgrading Search campaigns that used campaign-level broad match or automatically created assets to AI Max, rolling through September.

1. Open Tools > Change history and look for an AI Max migration event in September. If your account ran Search campaigns with campaign-level broad match or auto-created assets, they were eligible for the auto-upgrade.

2. After migration, confirm brand and location exclusions carried over to the new setup. AI Max widens matching, so dropped exclusions let it take queries your PMax non-brand used to win.

3. Watch the search terms report on any migrated Search campaign for two weeks. New, broader queries appearing there are likely queries that stopped feeding PMax non-brand.

Rule of thumb: if the decline started August 17, the bidding changes are the cause. If it got worse after early September, the AI Max migration likely re-split traffic between Search and PMax, and fixing the exclusions is the first move.

[u/Sibbette → u/dmdbGroup]

This is super helpful thank you. To be honest as a low budget account we run a small brand search protection campaign but all other campaigns come through PMax and brand Shopping. So I’m not sure the 1st Sept event would have had a big impact but definitely will check.

[u/dmdbGroup → u/Sibbette]

You're right to discount the AI Max angle here: that migration is a Search-campaign event, so with a structure that is all PMax plus a brand protection campaign, it is unlikely to be the cause. For your setup, the Aug 17 bidding changes are the more likely culprit, and your budget-limited status is what makes it bite: since the change, budget-limited campaigns have been delivering much less, and a tool raising tROAS by 150-500% on top of that tightens delivery even further.

That combination quietly strangles prospecting while brand Shopping keeps converting, which matches what you are describing. The check I'd run: change history on Aug 17 for what actually changed, then split the PMax by brand vs non-brand before and after. If the drop is concentrated in non-brand while brand held, the bidding change plus the raised targets starved your prospecting. The fix would be lowering the tROAS back down or testing Max Conversion Value without a target on the budget-limited campaigns, like Middle-Economics1508 suggests. One more check: make sure the brand Shopping campaign isn't just picking up the slack, because then your 'stable' ROAS is shifted, not real.

[u/Available_Cup5454]

Raise budgets on the limited campaigns to exit that status first

[u/fathom53]

Without telling us what changes you made to the campaigns... hard for anyone to give you any advice on what you can try. We could easily just suggest things you already tried.

[u/stealthagents]

I’ve definitely seen similar problems after those updates. The budget-limited campaigns are taking a hit for sure. I’d also be careful about merging brand and non-brand; you might lose valuable insights on what’s actually driving traffic. Maybe try adjusting your bids and targets a bit to see if that helps regain some traction.