Mastering Portfolio Budgets in Google Ads: When to Use Them, How to Set Them Up, and What to Watch Out For
Use them when you're scaling or looking to reduce micromanagement—but stay vigilant with data and always trust the metrics over assumptions.
Managing Google Ads campaigns effectively often means balancing performance across multiple campaigns, especially when they target different intents or geographies. As accounts scale, efficiency and budget allocation become just as important as campaign structure and keyword intent. This blog explores portfolio bid strategies with shared budgets in Google Ads—a powerful but often misunderstood and frequently neglected feature. Drawing on a real-world case study from a Tiga Digital client in the luxury fashion sector, we’ll explain when to use a portfolio budget, how to implement it, how to analyse performance, and what common pitfalls to avoid.
What Is a Portfolio Bid Strategy with a Shared Budget?
A portfolio bid strategy groups multiple campaigns under one unified bidding approach, such as "Maximise conversions" or "Target ROAS." Google then automatically adjusts bids across the campaigns in the portfolio based on the overall objective.
When combined with a shared budget, the system can dynamically allocate daily spend across campaigns—prioritising those more likely to convert and limiting spend on underperforming ones. This approach is useful for advertisers managing multiple campaigns that target similar customer journeys or stages in the funnel.
Case Study Overview: Luxury Fashion Campaigns
Let’s consider a real-world example from a Tiga Digital client in the luxury fashion sector:
| Metric | High-Intent Campaign | Hyper Local Campaign |
|---|---|---|
| Spend | £663.70 | £252.89 |
| Clicks | 331 | 109 |
| CTR | 7.93% | 5.94% |
| Conversions | 8.5 | 4.5 |
| Conversion Rate | 2.57% | 4.13% |
| Cost/Conversion | £78.08 | £56.20 |
Key Takeaways from the Data
The Hyper Local campaign is significantly more efficient, with a lower CPA and higher conversion rate.
The High-Intent campaign delivers more total conversions, but at a higher cost and with lower profitability.
Combining them under a portfolio strategy may allow Google to optimise for both volume and efficiency by redistributing the daily £45 budget dynamically.
Case Study Conclusion: What Happened After Launching the Portfolio Strategy?
After implementing the portfolio bid strategy and shared daily budget of £45, the client’s account began to stabilise within the first 10 days. Google quickly started allocating more budget to the Hyper Local campaign, which consistently delivered lower cost-per-lead.
By week three:
Conversions increased by 28% compared to the previous 30-day period
Average cost per lead dropped by 21%
The High-Intent campaign, now trimmed with tighter keyword exclusions and revised ad copy, also began to perform more efficiently within the shared framework
More importantly, the boutique began receiving a more consistent volume of qualified enquiries—many from customers who lived locally and were to spend. With fewer wasted clicks and better lead quality, the brand also reported an uplift in in-store conversions.
The marketing team, previously bogged down by budget micro-management, could now focus on CRO improvements and creative testing—knowing the ad spend was being directed intelligently.
The result? Higher-quality leads, a more scalable ad account, and a stronger return on time and investment.
| Metric | Before Portfolio Strategy | After Portfolio Strategy |
|---|---|---|
| Total Monthly Conversions | 13.0 | 16.6 (+28%) |
| Average Cost per Lead | £70.14 | £55.41 (–21%) |
| Conversion Rate (Across Campaigns) | 3.04% | 4.35% |
| Time Spent on Manual Budget Adjustments | High | Low |
| Lead Quality Feedback (Sales Team) | Inconsistent | Improved |
When Should You Use a Portfolio Strategy?
Use a portfolio budget when:
You have multiple campaigns targeting similar goals, e.g. lead generation or online purchases.
You want to automate bid adjustments across campaigns without managing them manually.
Some campaigns are under-performing but still valuable, and others are more efficient.
You want to scale performance intelligently based on real-time data.
In the case study, both campaigns aimed to generate high-value leads for a luxury boutique. One targeted local users in a high-end city area. The other targeted regional high-intent search terms. By consolidating bidding and budgets, performance could be scaled more efficiently.
How to Set Up a Portfolio Bid Strategy and Shared Budget
Here are the steps to implement it in Google Ads:
Choose the Right Strategy
Typically: Maximise conversions or Target CPA.
Ensure all campaigns have compatible goals and attribution models.
Create the Portfolio Strategy
Go to Tools > Bidding > Portfolio Bid Strategies.
Create a new strategy (e.g. Maximise Conversions).
Add Campaigns to the Portfolio
From the campaign settings, assign each campaign to the shared portfolio.
Create a Shared Budget
Tools > Shared Library > Budgets > New Shared Budget.
Set a total daily budget (e.g. £45/day).
Assign the Shared Budget
Apply this budget to all campaigns in the portfolio.
Monitor Performance Closely
Especially during the first 14 days.
Benefits of Portfolio Budgets
Greater Efficiency: Google shifts budget to whichever campaign is converting better in real-time.
Less Manual Work: One place to control multiple campaign budgets and bid strategies.
Smart Scaling: Google learns faster from aggregated data.
Better Budget Utilisation: Prevents waste on under-converting campaigns.
Risks and What to Watch Out For
Over-Favouring High Volume Campaigns
Google might favour the campaign with more impressions/clicks even if it's less efficient.
Lack of Granular Control
You can't set separate budgets per campaign anymore. Performance issues can hide behind portfolio averages.
Misaligned Goals
Don’t mix campaigns with different goals (e.g., lead gen and awareness).
Performance Dilution
You might miss that one campaign is pulling down the average unless you monitor campaign-level data.
Delayed Feedback Loops
Some optimisations may take longer to show results, especially if data is pooled.
How to Monitor Portfolio Strategy Performance
Campaign-Level Columns: Always check metrics like CPA, ROAS, and conversion rate per campaign.
Set Alerts: E.g., notify if CPA exceeds £70 on any campaign.
Use Segments: Break down data by device, location, or ad group to diagnose performance drivers.
Schedule Weekly Reviews: Evaluate cost/conversion and conversion value at both the campaign and portfolio level.
| Watch-Out | Why It Matters |
|---|---|
| Over-Favouring High Volume Campaigns | Google may allocate more budget to campaigns with higher impressions/clicks even if they convert less efficiently. |
| Lack of Granular Control | Portfolio budgets remove individual campaign caps, making it harder to isolate performance and control spend per campaign. |
| Misaligned Goals | Mixing campaigns with different conversion goals can confuse optimisation and reduce overall performance clarity. |
| Performance Dilution | Poor-performing campaigns can drag down overall results, especially if not monitored at the individual campaign level. |
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